Related
I need another set of eyes on this.
I've written out a zip file into hundreds of gigabytes with this exact code with no modifications locally on MacOSX.
With 100% unchanged code, just deployed to an AWS instance running Ubuntu, this same code runs into Out of Memory issues (heap space).
Here's the code that's being run, streaming MyBatis to a CSV file on disk:
File directory = new File(feedDirectory);
File file;
try {
file = File.createTempFile(("feed-" + providerCode + "-"), ".csv", directory);
} catch (IOException e) {
throw new RuntimeException("Unable to create file to write feed to disk: " + e.getMessage(), e);
}
String filePath = file.getAbsolutePath();
log.info(String.format("File name for %s feed is %s", providerCode, filePath));
// output file
try (FileOutputStream out = new FileOutputStream(file)) {
streamData(out, providerCode, startDate, endDate);
} catch (IOException e) {
throw new RuntimeException("Unable to write feed to file: " + e.getMessage());
}
public void streamData(OutputStream outputStream, String providerCode, Date startDate, Date endDate) throws IOException {
try (CSVPrinter printer = CsvUtil.openPrinter(outputStream)) {
StreamingHandler<FStay> handler = stayPrintingHandler(printer);
warehouse.doForAllStaysByProvider(providerCode, startDate, endDate, handler);
}
}
private StreamingHandler<FStay> stayPrintingHandler(CSVPrinter printer) {
StreamingHandler<FStay> handler = new StreamingHandler<>();
handler.setHandler((stay) -> {
try {
EXPORTER.writeStay(printer, stay);
} catch (IOException e) {
log.error("Issue with writing output: " + e.getMessage(), e);
}
});
return handler;
}
// The EXPORTER method
import org.apache.commons.csv.CSVPrinter;
public void writeStay(CSVPrinter printer, FStay stay) throws IOException {
List<Object> list = asList(stay);
printer.printRecord(list);
}
List<Object> asList(FStay stay) {
List<Object> list = new ArrayList<>(46);
list.add(stay.getUid());
list.add(stay.getProviderCode());
//....
return list;
}
Here's a graph of the JVM heap space (using jvisualvm) when I run this locally. I've run this consistently with of Java 8 (jdk1.8.0_51 and 1.8.0_112) locally and have gotten great results. Even written out a terabyte of data.
^ In the above, the max heap space is set to 4 gigs, and the most it ever increases to is 1.5 gigs, before going back down to around 500 MB, while streaming data to the CSV file as it's supposed to.
However, when I run this on Ubuntu with jdk 1.8.0_111, the exact same operation will not complete, running out of heap space (java.lang.OutOfMemoryError: Java heap space)
I've upped the Xmx value from 8 gigs to 16 to 25 gigs, and still run out of heap space. Meanwhile... the total size of the file is only 10 Gigs in total... which really perplexes me.
Here's what the JVisualVm graph looks like on the Ubuntu box:
I've no doubt it's the exact same code running in both environments, with the same operation being performed in each (same database server providing the same data)
The only differences I can think of at this point are:
Operating system - Ubuntu vs Mac OS X
Hosted VM in AWS vs hard metal laptop
Network speed is faster in AWS between database and Ubuntu server
JDK version is 1.8.0_111 in Ubuntu, tried 1.8.0_51 and 1.8.0_112 locally
Can anyone help shed any light on this problem?
Update
I've tried replacing all the 'try-with-resources' statements with explicit flush/close statements and no luck.
What's more, I tried to force a garbage collection on the Ubuntu box as soon as I started to see the data come in, and it had no effect-- there is something definitely stopping the heap from being collected on the Ubuntu machine... while running the exact same code on OS X let me write the full enchilada again no problem.
Update 2
In addition to the differences in the environments above, the only other difference I can think of is if the connection between the servers in AWS is so fast that it streams the data faster than it can flush the data to disk... but that still doesn't explain the issue where I only have 10 gigs of data total, and it blows up a JVM with 20 Gigs of heap space.
Is there any likelihood of there being a bug at the Ubuntu/Java level for this?
Update 3
Tried replacing the output of the CSVPrinter to use an entirely separate library (OpenCSV's CSVWriter in lieu of Apache's CSV library) and the same result occurs.
As soon as this code starts receiving data from the database, the heap starts blowing up and the garbage collector fails to reclaim any memory... but only on Ubuntu. On OS X, everything is reclaimed immediately and the heap never grows.
I've also tried flushing the stream after every write, but had no luck with that as well.
Update 4
Got the heap dump to print out, and according to this I should be looking at the database driver. Specifically the InboundDataHandler in amazon's redshift driver.
I'm using myBatis with a custom result handler. I tried setting the result handler to effectively do nothing when it gets a result (new ResultHandler<>() { // method overridden to do literally nothing}) and I know I'm not holding on to any references there.
Since it's the InboundDataHandler defined by AWS/Redshift... it makes me think it may be lower than the myBatis level... either:
Error in the SqlSessionFactory I'm setting up
Bug in the Redshift driver that only pops up in Ubuntu / AWS
Bug in the result handler I have overwritten
Here's the heap dump screenshot:
Here's where I'm setting up my SqlSessionFactoryBean:
#Bean
public javax.sql.DataSource redshiftDataSource() throws ClassNotFoundException {
log.info("Got to datasource config");
// Dynamically load driver at runtime.
Class.forName(dataWarehouseDriver);
DataSource dataSource = new DataSource();
dataSource.setURL(dataWarehouseUrl);
dataSource.setUserID(dataWarehouseUsername);
dataSource.setPassword(dataWarehousePassword);
return dataSource;
}
#Bean
public SqlSessionFactoryBean sqlSessionFactory() throws ClassNotFoundException {
SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
factoryBean.setDataSource(redshiftDataSource());
return factoryBean;
}
Here's the myBatis code I'm running as a test to verify that it's not me holding on to records in my ResultHandler:
warehouse.doForAllStaysByProvider(providerCode, startDate, endDate, new ResultHandler<FStay>() {
#Override
public void handleResult(ResultContext<? extends FStay> resultContext) {
// do nothing
}
});
Is there a way I can force the SQL connection to not hang on to records or something? I'll again re-iterate that on my local machine, there is no issue with this memory leak... it only surfaces when running the code in the hosted AWS environment. And in both cases, the Database driver and server are the same.
Update 6
I think it's finally fixed. Thanks to all who pointed me in the direction of the heap dump. That helped narrow it down to the offending class in a huge way.
After that, I did some research on the AWS redshift driver, and it explicitly says that your clients should specify a limit for any operations on large data. So I found out how to do that in my myBatis configuration:
<select id="doForAllStaysByProvider" fetchSize="1000" resultMap="FStayResultMap">
select distinct
f_stay.uid,
And this did the trick.
Mind you, this isn't necessary even when handling much larger data sets downloaded remotely from AWS (Database in AWS, code executing on laptop at home), and this shouldn't be necessary since I'm overriding the myBatis ResultHandler<> which handles each row individually and never holds on to any objects.
Yet something funky happens with the AWS redshift jdbc driver only when it's run in AWS (database in aws, code executing in AWS instance) which causes this InboundDataHandler to never release its resources, unless a fetchSize is specified.
Here's the heap of the server running now, getting much further than it ever has before in AWS, with the heap space never moving above 500Mb, and after i hit 'force gc' in jvisualvm, it shows the 'used' heap at less than 100mb:
Thanks again in a huge way to all those who helped guide this!
Finally figured out a solution.
The heap dump was the biggest aid-- it indicated the InboundDataHandler class of Amazon's RedShift/postgres JDCB driver was the prime culprit.
The code to set up the SqlSession appeared legit, so traveling over to Amazon's documentation landed this gem:
To avoid client-side out-of-memory errors when retrieving large data
sets using JDBC, you can enable your client to fetch data in batches
by setting the JDBC fetch size parameter.
We hadn't run into this before, as we stream results with custom ResultHandlers in MyBatis... but there seems to be something different when the AWS Redshift JDBC driver is running on AWS itself vs outside AWS connecting in.
Taking the guidance from the documentation, we added a 'fetchSize' to our MyBatis select query:
<select id="doForAllStaysByProvider" fetchSize="1000" resultMap="FStayResultMap">
select distinct
f_stay.uid,
And voila! Everything worked swimmingly. This is the only change we made and the heap never went above a couple hundred MBs.
You can see in one of the above graphs where the heap goes off the charts, as soon as the data started to be received on Amazon, the heap marches right up linearly and never reclaims an ounce of heap space once it starts.
My guess is the Redshift JDBC driver is doing something different when it's in Amazon's environment for some kind of optimization... that's all I can think of to explain the behavior.
Clearly Amazon knows what's going on since they documented it up front. I may not know the full 'why' of what's happening, but at least everything is resolved in what appears to be a satisfactory way.
Thanks to all those who helped.
I am just experimenting with the jt400.jar to receive system information from an AS400.
I figured out how to connect and how to receive values by using the class SystemStatus and how to read SystemValues. (only need to find an explanation for those values, any hints for me?)
Can anyone tell me, which of the functions in SystemStatus delivers me the usage of RAM or a poper way of receiving this information?
private static void getSystemStatus() throws AS400SecurityException, ErrorCompletingRequestException,
InterruptedException, IOException, ObjectDoesNotExistException, RequestNotSupportedException {
//Connect to AS400
AS400 as400 = new AS400("myAs400", "myUser", "myPassword");
//Reading SystemStatus like CPU usage and hdd usage
SystemStatus systemStatus = new SystemStatus(as400);
System.out.println(systemStatus.getPercentProcessingUnitUsed());
System.out.println(systemStatus.getActiveJobsInSystem());
//Reading SystemValues
SystemValueList sysValList = new SystemValueList(as400);
Vector<SystemValue> sysValVec = new Vector<SystemValue>();
sysValVec = sysValList.getGroup(SystemValueList.GROUP_ALL);
System.out.println("<<<< SystemValues >>>>");
for (SystemValue systemValue : sysValVec) {
String sysValName = systemValue.getName();
systemValue.getValue();
System.out.println("Value: " + sysValName + " - " + systemValue.getValue());
}
System.out.println("<<<< SystemValues >>>>");
}
I already read a lot of documentation but was not able to find anything.
http://www-01.ibm.com/support/knowledgecenter/ssw_ibm_i_71/rzahh/as400obj.htm
http://itknowledgeexchange.techtarget.com/itanswers/system-information-into-a-file/
http://www.ibm.com/developerworks/ibmi/library/i-javatoolbox/
Thanks in advance
I don't think you're going to find that information.
IBM i Operating System, (aka OS/400) doesn't see RAM & HDD separately. Instead, it sees a single large address space known as the single level store.
http://db2fori.blogspot.com/2012/11/one-of-crown-jewels-single-level-storage.html
Certainly the low level Technology Independent Machine Interface (TIMI) knows about RAM/SSD/HDD. But that's buried deep. IBM surfaces some of that information via it's own command such as
Work Disk Status (WRKDSKSTS)
Size %
Unit Type (M) Used
1 4327 52923 68.9
2 4327 52923 68.9
But memory is basically always 100% used. The system basically treats all RAM as a cache for objects from auxiliary (SSD/HDD) storage.
#Charles answered the question about RAM usage.
With respect to System Values, a System Value is a... configuration item for the host system. An example is QDATFMT which describes the way a data is displayed, 03-31-2016 or 31.03.6, etc. Generally, the System Administrator is most interested in System Values. The Knowledge Center explains System Values: http://www-01.ibm.com/support/knowledgecenter/ssw_ibm_i_72/rzakz/rzakz1.htm?lang=en
I'd like to get an id unique to a computer with Java, on Windows, MacOS and, if possible, Linux. It could be a disk UUID, motherboard S/N...
Runtime.getRuntime().exec can be used (it is not an applet).
Ideas?
The problem with MAC address is that there can be many network adapters connected to the computer. Most of the newest ones have two by default (wi-fi + cable). In such situation one would have to know which adapter's MAC address should be used. I tested MAC solution on my system, but I have 4 adapters (cable, WiFi, TAP adapter for Virtual Box and one for Bluetooth) and I was not able to decide which MAC I should take... If one would decide to use adapter which is currently in use (has addresses assigned) then new problem appears since someone can take his/her laptop and switch from cable adapter to wi-fi. With such condition MAC stored when laptop was connected through cable will now be invalid.
For example those are adapters I found in my system:
lo MS TCP Loopback interface
eth0 Intel(R) Centrino(R) Advanced-N 6205
eth1 Intel(R) 82579LM Gigabit Network Connection
eth2 VirtualBox Host-Only Ethernet Adapter
eth3 Sterownik serwera dostepu do sieci LAN Bluetooth
Code I've used to list them:
Enumeration<NetworkInterface> nis = NetworkInterface.getNetworkInterfaces();
while (nis.hasMoreElements()) {
NetworkInterface ni = nis.nextElement();
System.out.println(ni.getName() + " " + ni.getDisplayName());
}
From the options listen on this page, the most acceptable for me, and the one I've used in my solution is the one by #Ozhan Duz, the other one, similar to #finnw answer where he used JACOB, and worth mentioning is com4j - sample which makes use of WMI is available here:
ISWbemLocator wbemLocator = ClassFactory.createSWbemLocator();
ISWbemServices wbemServices = wbemLocator.connectServer("localhost","Root\\CIMv2","","","","",0,null);
ISWbemObjectSet result = wbemServices.execQuery("Select * from Win32_SystemEnclosure","WQL",16,null);
for(Com4jObject obj : result) {
ISWbemObject wo = obj.queryInterface(ISWbemObject.class);
System.out.println(wo.getObjectText_(0));
}
This will print some computer information together with computer Serial Number. Please note that all classes required by this example has to be generated by maven-com4j-plugin. Example configuration for maven-com4j-plugin:
<plugin>
<groupId>org.jvnet.com4j</groupId>
<artifactId>maven-com4j-plugin</artifactId>
<version>1.0</version>
<configuration>
<libId>565783C6-CB41-11D1-8B02-00600806D9B6</libId>
<package>win.wmi</package>
<outputDirectory>${project.build.directory}/generated-sources/com4j</outputDirectory>
</configuration>
<executions>
<execution>
<id>generate-wmi-bridge</id>
<goals>
<goal>gen</goal>
</goals>
</execution>
</executions>
</plugin>
Above's configuration will tell plugin to generate classes in target/generated-sources/com4j directory in the project folder.
For those who would like to see ready-to-use solution, I'm including links to the three classes I wrote to get machine SN on Windows, Linux and Mac OS:
Java code to get computer SN on Windows
Java code to get computer SN on Linux
Java code to get computer SN on Mac OS
The OSHI project provides platform-independent hardware utilities.
Maven dependency:
<dependency>
<groupId>com.github.oshi</groupId>
<artifactId>oshi-core</artifactId>
<version>LATEST</version>
</dependency>
For instance, you could use something like the following code to identify a machine uniquely:
import oshi.SystemInfo;
import oshi.hardware.CentralProcessor;
import oshi.hardware.ComputerSystem;
import oshi.hardware.HardwareAbstractionLayer;
import oshi.software.os.OperatingSystem;
class ComputerIdentifier
{
static String generateLicenseKey()
{
SystemInfo systemInfo = new SystemInfo();
OperatingSystem operatingSystem = systemInfo.getOperatingSystem();
HardwareAbstractionLayer hardwareAbstractionLayer = systemInfo.getHardware();
CentralProcessor centralProcessor = hardwareAbstractionLayer.getProcessor();
ComputerSystem computerSystem = hardwareAbstractionLayer.getComputerSystem();
String vendor = operatingSystem.getManufacturer();
String processorSerialNumber = computerSystem.getSerialNumber();
String processorIdentifier = centralProcessor.getIdentifier();
int processors = centralProcessor.getLogicalProcessorCount();
String delimiter = "#";
return vendor +
delimiter +
processorSerialNumber +
delimiter +
processorIdentifier +
delimiter +
processors;
}
public static void main(String[] arguments)
{
String identifier = generateLicenseKey();
System.out.println(identifier);
}
}
Output for my machine:
Microsoft#57YRD12#Intel64 Family 6 Model 60 Stepping 3#8
Your output will be different since at least the processor serial number will differ.
It is common to use the MAC address is associated with the network card.
The address is available in Java 6 through through the following API:
Java 6 Docs for Hardware Address
I haven't used it in Java, but for other network identification applications it has been helpful.
What do you want to do with this unique ID? Maybe you can do what you want without this ID.
The MAC address maybe is one option but this is not an trusted unique ID because the user can change the MAC address of a computer.
To get the motherboard or processor ID check on this link.
On Windows only, you can get the motherboard ID using WMI, through a COM bridge such as JACOB.
Example:
import java.util.Enumeration;
import com.jacob.activeX.ActiveXComponent;
import com.jacob.com.ComThread;
import com.jacob.com.EnumVariant;
import com.jacob.com.Variant;
public class Test {
public static void main(String[] args) {
ComThread.InitMTA();
try {
ActiveXComponent wmi = new ActiveXComponent("winmgmts:\\\\.");
Variant instances = wmi.invoke("InstancesOf", "Win32_BaseBoard");
Enumeration<Variant> en = new EnumVariant(instances.getDispatch());
while (en.hasMoreElements())
{
ActiveXComponent bb = new ActiveXComponent(en.nextElement().getDispatch());
System.out.println(bb.getPropertyAsString("SerialNumber"));
break;
}
} finally {
ComThread.Release();
}
}
}
And if you choose to use the MAC address to identify the machine, you can use WMI to determine whether an interface is connected via USB (if you want to exclude USB adapters.)
It's also possible to get a hard drive ID via WMI but this is unreliable.
Not Knowing all of your requirements. For example, are you trying to uniquely identify a computer from all of the computers in the world, or are you just trying to uniquely identify a computer from a set of users of your application. Also, can you create files on the system?
If you are able to create a file. You could create a file and use the creation time of the file as your unique id. If you create it in user space then it would uniquely identify a user of your application on a particular machine. If you created it somewhere global then it could uniquely identify the machine.
Again, as most things, How fast is fast enough.. or in this case, how unique is unique enough.
Be careful when using the MAC address as an identifier. I've experienced several gotchas:
On OS X, ethernet ports that are not active/up do not show up in the NetworkInterface.getNetworkInterfaces() Enumeration.
It's insanely easy to change a MAC address on cards if you've got appropriate OS privileges.
Java has a habit of not correctly identifying "virtual" interfaces. Even using the NetworkInterface.isVirtual() won't always tell you the truth.
Even with the above issues, I still think it's the best pure Java approach to hardware locking a license.
I think you should look at this link ... you can make a mixed key using several
identifiers such as mac+os+hostname+cpu id+motherboard serial number.
The usage of MAC id is most easier way if the task is about logging the unique id a system.
the change of mac id is though possible, even the change of other ids of a system are also possible is that respective device is replaced.
so, unless what for a unique id is required is not known, we may not be able to find an appropriate solution.
However, the below link is helpful extracting mac addresses.
http://www.stratos.me/2008/07/find-mac-address-using-java/
For identifying a windows machine uniquely.
Make sure when you use wmic to have a strategy of alternative methods. Since "wmic bios get serialnumber" might not work on all machines, you might need to have additional methods:
# Get serial number from bios
wmic bios get serialnumber
# If previous fails, get UUID
wmic csproduct get UUID
# If previous fails, get diskdrive serialnumber
wmic DISKDRIVE get SerialNumber
Resources:
The Best Way To Uniquely Identify A Windows Machine
http://www.nextofwindows.com/the-best-way-to-uniquely-identify-a-windows-machine/
In the java programs I have written for release I used the motherboard serial number (which is what I beleive windows use); however, this only works on windows as my function creates a temporary VB script which uses the WMI to retrieve the value.
public static String getMotherboardSerial() {
String result = "";
try {
File file = File.createTempFile("GetMBSerial",".vbs");
file.deleteOnExit();
FileWriter fw = new FileWriter(file);
String vbs =
"Set objWMIService = GetObject(\"winmgmts:\\\\.\\root\\cimv2\")\n"
+ "Set colItems = objWMIService.ExecQuery _ \n"
+ " (\"Select * from Win32_ComputerSystemProduct\") \n"
+ "For Each objItem in colItems \n"
+ " Wscript.Echo objItem.IdentifyingNumber \n"
+ "Next \n";
fw.write(vbs);
fw.close();
Process gWMI = Runtime.getRuntime().exec("cscript //NoLogo " + file.getPath());
BufferedReader input = new BufferedReader(new InputStreamReader(gWMI.getInputStream()));
String line;
while ((line = input.readLine()) != null) {
result += line;
System.out.println(line);
}
input.close();
}
catch(Exception e){
e.printStackTrace();
}
result = result.trim();
return result;
}
I need your help about performance problems running our corporate Java application on HP\UX server. Application is standalone tool which synchronizes data over several data bases into one, communicates with remote control on XML-RPC protocol and uses local Derby (Java DB) data base instance to hold configuration data etc. We don not have performance problems on other environments on the same load like Windows XP, Linux and AIX which use Sun JVM. After series of test we found out that most time consuming was communication with Derby data base. Most time is spent on reading from socket and this time is greater in 10-100 times than on other platforms. We know for sure that Derby works fine, we’ve got CPU reserve (usage is about 30%-40%), so most probable reason is transport layer between local data base and application.
Is there a way to diagnose socket I\O problems on HP-UX or maybe there is some possible limitations that can be configured? Maybe there is necessary JVM option? Any ideas from your side would be highly appreciated.
We’ve tried to optimize JVM options according to http://publib.boulder.ibm.com/infocenter/wasinfo/v6r1/index.jsp?topic=/com.ibm.websphere.wsfep.multiplatform.doc/info/ae/ae/tprf_tunejvm_v61.html but didn’t get any significant improvement.
JVM info:
Java HotSpot(TM) 64-Bit Server VM (19.1-b02-jinteg:2011mar11-16:46 PA2.0W (aCC_AP), mixed mode)
Java: version 1.6.0.10, vendor "Hewlett-Packard Company"
We use following instance:
OS: HP-UX (B.11.23)
Architecture: PA_RISC2.0W 64bit
Processors: 2
Total physical memory size: 4 088 MB
Swap size: 4 090 MB
Here is example of slow running code. It takes several seconds to execute on HP while on Windows it takes 10-30ms:
/** Template to communicate with local db. */
SimpleJdbcTemplate jdbcTemplate;
#Transactional(readOnly = true)
public List<JobLogEntry> getLastLogs(Integer dbnr, JobDataType dtype) {
try {
String uid = jdbcTemplate.queryForObject("SELECT session_uuid FROM "
+ tableName + " WHERE id=(SELECT max(id) FROM "
+ tableName + " WHERE dbnr=? AND dtype=?)",
String.class, dbnr, dtype.name());
List<JobLogEntry> list = jdbcTemplate.query("SELECT id, dbnr, dtype, zeit, level, message FROM "
+ tableName
+ " WHERE dbnr=? AND dtype=? AND session_uuid=? ORDER BY ID",
new ConRowMapper(), dbnr, dtype.name(), uid);
return list;
} catch (org.springframework.dao.EmptyResultDataAccessException e) {
return new ArrayList<JobLogEntry>();
}
}
class ConRowMapper implements RowMapper<JobLogEntry> {
private final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy.MM.dd HH:mm:ss");
/**
* Maps rows.
*/
public JobLogEntry mapRow(ResultSet rs, int rowNum) throws SQLException {
return new JobLogEntry(rs.getInt("dbnr"),
rs.getString("dtype"),
dateFormat.format(rs.getTimestamp("zeit")),
rs.getString("level"),
rs.getString("message"));
}
}
Thanks in advance for all your ideas
I wonder about the method getLastLogs(). Why query to get the session UUID and then turn around and use it in another query? I would guess that it's possible to do it in one query.
When you say Derby, it makes me think that only Java accesses that database. Is that true? Do you know that it's optimized well (e.g. proper indexes for every WHERE clause)?
Do you use connection pooling? That way you can pay the cost of creating connections up front and amortize it over all the queries you run.
I see jdbcTemplate, so you must be using Spring. I'd get the debug or trace interceptor wired in and see where the time is being spent.
I'd also recommend Visual VM 1.3.2 will all the plugins installed. It will give you a lot more data.
Probable reason could be slow and blockong GC work on HP-UX. Try removing redundant System.gc() calls and use some JVM GC options to otimize :)
See nice presentation about HP performance tuning: http://www.scribd.com/doc/47433278/Javamemorymanagemen
I'd like to get an id unique to a computer with Java, on Windows, MacOS and, if possible, Linux. It could be a disk UUID, motherboard S/N...
Runtime.getRuntime().exec can be used (it is not an applet).
Ideas?
The problem with MAC address is that there can be many network adapters connected to the computer. Most of the newest ones have two by default (wi-fi + cable). In such situation one would have to know which adapter's MAC address should be used. I tested MAC solution on my system, but I have 4 adapters (cable, WiFi, TAP adapter for Virtual Box and one for Bluetooth) and I was not able to decide which MAC I should take... If one would decide to use adapter which is currently in use (has addresses assigned) then new problem appears since someone can take his/her laptop and switch from cable adapter to wi-fi. With such condition MAC stored when laptop was connected through cable will now be invalid.
For example those are adapters I found in my system:
lo MS TCP Loopback interface
eth0 Intel(R) Centrino(R) Advanced-N 6205
eth1 Intel(R) 82579LM Gigabit Network Connection
eth2 VirtualBox Host-Only Ethernet Adapter
eth3 Sterownik serwera dostepu do sieci LAN Bluetooth
Code I've used to list them:
Enumeration<NetworkInterface> nis = NetworkInterface.getNetworkInterfaces();
while (nis.hasMoreElements()) {
NetworkInterface ni = nis.nextElement();
System.out.println(ni.getName() + " " + ni.getDisplayName());
}
From the options listen on this page, the most acceptable for me, and the one I've used in my solution is the one by #Ozhan Duz, the other one, similar to #finnw answer where he used JACOB, and worth mentioning is com4j - sample which makes use of WMI is available here:
ISWbemLocator wbemLocator = ClassFactory.createSWbemLocator();
ISWbemServices wbemServices = wbemLocator.connectServer("localhost","Root\\CIMv2","","","","",0,null);
ISWbemObjectSet result = wbemServices.execQuery("Select * from Win32_SystemEnclosure","WQL",16,null);
for(Com4jObject obj : result) {
ISWbemObject wo = obj.queryInterface(ISWbemObject.class);
System.out.println(wo.getObjectText_(0));
}
This will print some computer information together with computer Serial Number. Please note that all classes required by this example has to be generated by maven-com4j-plugin. Example configuration for maven-com4j-plugin:
<plugin>
<groupId>org.jvnet.com4j</groupId>
<artifactId>maven-com4j-plugin</artifactId>
<version>1.0</version>
<configuration>
<libId>565783C6-CB41-11D1-8B02-00600806D9B6</libId>
<package>win.wmi</package>
<outputDirectory>${project.build.directory}/generated-sources/com4j</outputDirectory>
</configuration>
<executions>
<execution>
<id>generate-wmi-bridge</id>
<goals>
<goal>gen</goal>
</goals>
</execution>
</executions>
</plugin>
Above's configuration will tell plugin to generate classes in target/generated-sources/com4j directory in the project folder.
For those who would like to see ready-to-use solution, I'm including links to the three classes I wrote to get machine SN on Windows, Linux and Mac OS:
Java code to get computer SN on Windows
Java code to get computer SN on Linux
Java code to get computer SN on Mac OS
The OSHI project provides platform-independent hardware utilities.
Maven dependency:
<dependency>
<groupId>com.github.oshi</groupId>
<artifactId>oshi-core</artifactId>
<version>LATEST</version>
</dependency>
For instance, you could use something like the following code to identify a machine uniquely:
import oshi.SystemInfo;
import oshi.hardware.CentralProcessor;
import oshi.hardware.ComputerSystem;
import oshi.hardware.HardwareAbstractionLayer;
import oshi.software.os.OperatingSystem;
class ComputerIdentifier
{
static String generateLicenseKey()
{
SystemInfo systemInfo = new SystemInfo();
OperatingSystem operatingSystem = systemInfo.getOperatingSystem();
HardwareAbstractionLayer hardwareAbstractionLayer = systemInfo.getHardware();
CentralProcessor centralProcessor = hardwareAbstractionLayer.getProcessor();
ComputerSystem computerSystem = hardwareAbstractionLayer.getComputerSystem();
String vendor = operatingSystem.getManufacturer();
String processorSerialNumber = computerSystem.getSerialNumber();
String processorIdentifier = centralProcessor.getIdentifier();
int processors = centralProcessor.getLogicalProcessorCount();
String delimiter = "#";
return vendor +
delimiter +
processorSerialNumber +
delimiter +
processorIdentifier +
delimiter +
processors;
}
public static void main(String[] arguments)
{
String identifier = generateLicenseKey();
System.out.println(identifier);
}
}
Output for my machine:
Microsoft#57YRD12#Intel64 Family 6 Model 60 Stepping 3#8
Your output will be different since at least the processor serial number will differ.
It is common to use the MAC address is associated with the network card.
The address is available in Java 6 through through the following API:
Java 6 Docs for Hardware Address
I haven't used it in Java, but for other network identification applications it has been helpful.
What do you want to do with this unique ID? Maybe you can do what you want without this ID.
The MAC address maybe is one option but this is not an trusted unique ID because the user can change the MAC address of a computer.
To get the motherboard or processor ID check on this link.
On Windows only, you can get the motherboard ID using WMI, through a COM bridge such as JACOB.
Example:
import java.util.Enumeration;
import com.jacob.activeX.ActiveXComponent;
import com.jacob.com.ComThread;
import com.jacob.com.EnumVariant;
import com.jacob.com.Variant;
public class Test {
public static void main(String[] args) {
ComThread.InitMTA();
try {
ActiveXComponent wmi = new ActiveXComponent("winmgmts:\\\\.");
Variant instances = wmi.invoke("InstancesOf", "Win32_BaseBoard");
Enumeration<Variant> en = new EnumVariant(instances.getDispatch());
while (en.hasMoreElements())
{
ActiveXComponent bb = new ActiveXComponent(en.nextElement().getDispatch());
System.out.println(bb.getPropertyAsString("SerialNumber"));
break;
}
} finally {
ComThread.Release();
}
}
}
And if you choose to use the MAC address to identify the machine, you can use WMI to determine whether an interface is connected via USB (if you want to exclude USB adapters.)
It's also possible to get a hard drive ID via WMI but this is unreliable.
Not Knowing all of your requirements. For example, are you trying to uniquely identify a computer from all of the computers in the world, or are you just trying to uniquely identify a computer from a set of users of your application. Also, can you create files on the system?
If you are able to create a file. You could create a file and use the creation time of the file as your unique id. If you create it in user space then it would uniquely identify a user of your application on a particular machine. If you created it somewhere global then it could uniquely identify the machine.
Again, as most things, How fast is fast enough.. or in this case, how unique is unique enough.
Be careful when using the MAC address as an identifier. I've experienced several gotchas:
On OS X, ethernet ports that are not active/up do not show up in the NetworkInterface.getNetworkInterfaces() Enumeration.
It's insanely easy to change a MAC address on cards if you've got appropriate OS privileges.
Java has a habit of not correctly identifying "virtual" interfaces. Even using the NetworkInterface.isVirtual() won't always tell you the truth.
Even with the above issues, I still think it's the best pure Java approach to hardware locking a license.
I think you should look at this link ... you can make a mixed key using several
identifiers such as mac+os+hostname+cpu id+motherboard serial number.
The usage of MAC id is most easier way if the task is about logging the unique id a system.
the change of mac id is though possible, even the change of other ids of a system are also possible is that respective device is replaced.
so, unless what for a unique id is required is not known, we may not be able to find an appropriate solution.
However, the below link is helpful extracting mac addresses.
http://www.stratos.me/2008/07/find-mac-address-using-java/
For identifying a windows machine uniquely.
Make sure when you use wmic to have a strategy of alternative methods. Since "wmic bios get serialnumber" might not work on all machines, you might need to have additional methods:
# Get serial number from bios
wmic bios get serialnumber
# If previous fails, get UUID
wmic csproduct get UUID
# If previous fails, get diskdrive serialnumber
wmic DISKDRIVE get SerialNumber
Resources:
The Best Way To Uniquely Identify A Windows Machine
http://www.nextofwindows.com/the-best-way-to-uniquely-identify-a-windows-machine/
In the java programs I have written for release I used the motherboard serial number (which is what I beleive windows use); however, this only works on windows as my function creates a temporary VB script which uses the WMI to retrieve the value.
public static String getMotherboardSerial() {
String result = "";
try {
File file = File.createTempFile("GetMBSerial",".vbs");
file.deleteOnExit();
FileWriter fw = new FileWriter(file);
String vbs =
"Set objWMIService = GetObject(\"winmgmts:\\\\.\\root\\cimv2\")\n"
+ "Set colItems = objWMIService.ExecQuery _ \n"
+ " (\"Select * from Win32_ComputerSystemProduct\") \n"
+ "For Each objItem in colItems \n"
+ " Wscript.Echo objItem.IdentifyingNumber \n"
+ "Next \n";
fw.write(vbs);
fw.close();
Process gWMI = Runtime.getRuntime().exec("cscript //NoLogo " + file.getPath());
BufferedReader input = new BufferedReader(new InputStreamReader(gWMI.getInputStream()));
String line;
while ((line = input.readLine()) != null) {
result += line;
System.out.println(line);
}
input.close();
}
catch(Exception e){
e.printStackTrace();
}
result = result.trim();
return result;
}