I am really new to database and this is my first program in database using java Netbeans 7.1 --- It is summer on our country now and I am a student with the course I.T. Our next subject on programming is about database and since there's no class I spend my time learning database for preparation for the next school semester and I refer to this site as my guide for the first database program I currently making now.
http://www.homeandlearn.co.uk/java/databases_and_java_forms.html
I did everything in the tutorial and I actually done doing the program.
The final thing I did is I clean and build the program since I want the program to run with out opening the netbeans again I downloaded the JRE and make my database_form.jar as a jar executable. "database_form" the name of my Netbeans Project. I do that by making javaw in JRE.7 as my dafault when opening any jar files.
Anyway, this is how i run the program.
Running Program in Netbeans IDE
Using Netbeans, before my program works I first need to "Start Server" on JavaDB. because if I didn't do that an Exception occurred "Err. connecting to server localhost 1527 and so on"
Running Program using jar executable alone.
The Problem is there's an Exception and Err in connecting still occurred.
What I want to achieve?
I want the program to run without opening the Netbeans IDE and going to Java DB to click the "Start Server", I dont want to do that anymore. Or my second option is to start the server using command prompt so that I just have to make a bat file so that whenever I open my program database_form.jar I just place the bat file on my desktop and run it.
Second Problem!
Actually, I already try my second option by using command prompt to start the server but I forgot how I did it, I just found it on some website the only thing I remember is the Exception says "Failed to lunch the server because the database Employees is missing. Employees is the name of my created database.
The O.S. I am using is Windows 7.
Thank you for all the reply and sorry for the long text I just want to be specific, :D
Right, from your description there seems to be a couple of things you are confusing.
First, databases are typically run as servers with multiple clients connecting to them thus allowing they contain to be shared. When you start Java DB you are starting the Java DB database server.
That said, lightweight databases, such as Java DB can be run in an embedded mode as explained here. Remember that the directory you point to with the derby.system.home property will need to contain the database files, if not you'll need to create that programatically too.
Second, there's various ways to run a Java application outside of an IDE, but jars themselves are not executable in the same way an exe file is in Windows.
The simplest way is to call the java executable passing the necessary classpath and the name of the class containing the main method. For example if I had a class called com.example.Application that had been compiled to a directory C:\dev\example\classes the following command line would run the application:
java -cp C:\dev\example\classes com.example.Application
If there were dependencies on external libraries, as there will be in your case on the Derby JDBC driver, then those would also need including in the classpath resulting in something like:
java -cp C:\dev\example\classes;C:\dev\lib\derby.jar com.example.Application
There's a full set of document on the Java launcher here.
Now, back to the jar. Like I said, jars are not executable but there is something that's know as an 'executable jar'. This is the same as any jar except there are some special additions to the manifest to specify the application entry point or main-class and the class-path as described here.
Once the main-class and class-path are specified in the jar's manifest, the following command line would run the application:
java -jar C:\dev\example.jar
You can even associate the jar extension with the java exe and double clicking the jar will cause the application to launch (though on a dev machine it's probably more useful that the jar extension be associated with WinZip or simlar in order to open that jar).
The default database in Netbeans is Derby/JavaDB. So you need to:
add the jar of javadb/derby in our classpath (it maybe already present, as it is bundled with java when you install it in Ubuntu)
setup a path with the jdbc URI to save the database data
I personally recommend the usage of hsqldb or H2 for this: they support in-memory database, very useful for stand alone project with no persistence data or for tests.
If you use window, add ODBC Data Sources from Administrative Tools to your Java Derby driver and run jar.
Related
I'm re-using a standalone Swing-based Java class which backs up and restores mysql databases.
I've tested running it from a Windows batch file (.bat) on my dev system, and it works there.
But, if I run the batch file on a different Windows , I get a "main class not found" exception.
However, when I run the command directly on the command line, it works.
The command in the batch file to run it is:
java -cp lda-services.jar;bip-services-1.6.0.0-SNAPSHOT.jar;decryptor-1.6.0.0-SNAPSHOT.jar;slf4j-api-1.7.31.jar;commons-io-2.6.jar com.ilcore.util.SosaMaintenanceJFrame
The SosaMaintenanceJFrame class is contained in the lda-services jar.
Here's the error message:
Error: Could not find or load main class com.ilcore.util.SosaMaintenanceJFrame
Caused by: java.lang.ClassNotFoundException: com.ilcore.util.SosaMaintenanceJFrame
The class is definitely in the jar file, as I've extracted it the file and seen it.
Any thoughts on why this would be happening? I need to run inside a batch file so the user can just click on it to run it.
Most likely explanation
Your paths are relative, which means that the batch file isn't going to work unless you run it from the right place. In general, having a batch file that has an invisible rider stapled to it with: "I break in mysterious ways if not run from the appropriate dir" is a crappy batch file - make it better.
Better solution
Or, even better, get rid of it. You don't need batch files to distribute java programs.
Proper ways to distribute java programs:
The modern take is very very different from what you have here: JREs are dead, you must ship an installer that does the whole thing, notably including a java runtime (no longer called a JRE, and one you ship and keep up to date if relevant). That's perhaps a bridge too far for what you're doing here. Relevant tools include jlink.
A slightly less modern take involves jars with manifests:
Your jar file should contain a manifest. This manifest must contain 2 relevant entries:
Class-Path: lda-services.jar bip-services-1.6.0.0-SNAPSHOT.jar decryptor-1.6.0.0-SNAPSHOT.jar slf4j-api-1.7.31.jar commons-io-2.6.jar
and
Main-Class: com.ilcore.util.SosaMaintenanceJFrame
You can use jar's -m switch, or just include the manifest (it's just a file in the jar): it's at META_INF/MANIFEST.MF and it's a text file, each line is an entry, and an entry consists of a key: value pair.
When a jar contains this, just double clicking the jar and running java -jar thejar.jar will then take care of it all: Java will load the stated jars as part of the classpath, and these, crucially, are resolved as paths relative to the directory the jar is in, so it DOES work when you try to launch them from elsewhere, i.e. if you do:
C:
CD \
java -jar "c:\Program Files\MyApp\myapp.jar"
it works fine, whereas that batch script would fail due to being in the wrong place.
Build systems let you define the manifest too, check your build systems docs for how to do this, it'll be easy, and there are tons of tutorials if you search the web for e.g. 'manifest executable jar maven' or whatnot.
You can consider making a shaded jar. But I wouldn't.
A shaded jar takes all your dependencies and packs them into your main jar, so that there is only one jar. There is now no need for a Class-Path entry (the jar you run is obviously already on the classpath and there's nothing else to include) and your app is shipped as 'just' a single jar file.
But this is mostly a red herring: There are no consumer JREs anymore so you've made the user experience from a D- to a D. If you actually care about giving your users a nice experience, there's no getting around an installation process of some sort and once you have that, having the separate jars is no longer a problem. Separate jars are less hairy when signed jars are involved, are much easier to keep up to date, and have a significantly faster turnaround (when you build your stuff and want to ship what you built, shading takes ages, so it's nice to cut that step out). The faster your CI system tells you about failing tests, the better.
Meet in the middle
You don't have to upgrade to modules and the like. What you can do instead is use something like launch4j. The aim is to end up with a zip file along with the installation instructions: Make a dir somewhere. unzip this zip in it. Doubleclick 'myapp.exe'. Done.
The zip would contain an entire JRE, all your jar file deps, and your main app, and an exe file which launch4j made for you, that launches your app using the JRE packed into the jar. This means you know exactly which JRE is being used, and it'll work even on systems that didn't have one installed yet (which, these days, should be all of them - the notion of 'end user downloads a JRE from oracle and the user + oracle work together to keep that thing up to date and security-issue-free', is dead).
The fact that it's an EXE is nice: Now if the user e.g. alt+tabs through their apps, they get your app, with your name, and your icon, instead of 'javaw.exe' with an ugly coffee mug logo.
But when I try running it from the jar file generated by Maven, however, I get a "class not found" exception.
Even if you didn't get that error, you'd get another one unless you'd used Maven Shade, as that's the only way you're going to run that with a single jar. My guess as to why that particular error occurs is that the app class you're attempting to run is in fact in one of the *SNAPSHOT* jars
I created a java GUI application using java.awt. The basic idea off the app is to query a mongo database using the mongo-java driver.
When running the code from the command prompt, the GUI opens up and it can interact with the initialized mongod server just fine with no problem. However, when I create a jar executable with the same class, the GUI opens up fine, yet none of the server interactions seem to occur.
For instance, when running the non-jar version, the mongod server running in the background displays something along the lines of: Sat Dec 14 09:14:20.347 [initandlisten] connection accepted from 127.0.0.1:XXXX #5 (1 connection now open), yet when running the jar version (without making any changes to the source code at all, literally the same exact .java and .class files), I don't see any of the conection statuses on the server.
I doubt you need me to insert all my code into this post, but here are the details that I think are most relevant to my issue. Let me know if you need any other details.
when creating my jar I used the command:
jar cvfm MongoDBGUI.jar manifest.txt *.class
manifest.txt has the line:
Main-Class: MongoDBGUI
*MongoDBGUI being the class with the main function
My crystal ball says that you've been swallowing exceptions in your code, so when something goes wrong, you have no logging to tell you what the error was.
My tarot cards tell me that you don't have the driver packaged inside your jar, so the driver isn't found. But my ouija board claims that you do have the driver inside the jar, it's just not configured properly in the classpath in MANIFEST.MF.
I can't get any pages of my webapp to load (locally on Tomcat 7.0.2.6), due to this NoClassDefFound error. I'm at my wits end trying to figure out what the cause is, here is what I know:
My coworker has this project successfully running locally (on Tomcat) and on our development server (WebLogic).
I have done a fresh pulldown from svn so my code is exactly the same as his. I've verified that I have a shared library reference to Aspose (and that the required .jars are in there), and that weblogic.xml has an entry for it.
We saw this same error when initially deploying on WebLogic because the Aspose library was named incorrectly, but it ran fine locally on his Tomcat server.
I've tried cleaning and rebuilding the project to no effect.
As best as I can figure, it has to be either a Tomcat issue, or maybe an Eclipse setting.
Has anyone encountered a similar situation? Any ideas on what to try to resolve this?
First thing you need to do is determine if you are colliding with another class with the same name and package. The easiest way to do this is with the cygwin/linux console, save this shell script to a file say, findjar
find "$1" -name "*.jar" -exec sh -c 'jar -tf {}|grep -H --label {} '$2'' \;
put it in your path and navigate to the root of the server instance and run the script like this
findjar . yourclass
Note the period, dont forget it. this will return if you have multiple classes with the same name in your project.
once your sure the project is clean and there is only one copy of the class, i would try actually adding your shared libraries folder to the websphere server instances JVM arguments. to do that:
Go into the admin, click on servers
Open server types, click on websphere application servers
You should see your server listed there, click on it
On the right hand side, you will see a section “server infrastructure” and below that is a subsection “Java and process Management”
Open that section and click on “Process Definition”
On the process definition screen is another right hand column. Click on “Java Virtual Machine”
Yes, finally we are on the correct screen, there is an end in sight here, I promise
On the virtual machine page, there is a large text field labeled “Classpath” What you need to do is enter the full path to the shared libraries folder
its odd and makes no sense to have to do it, but i have had to do that in the past to allow my code to see the properties files in a shared resource.
It is possible that your colleague has java librarys installed within his Tomcat instance itself.
Take a look in the Tomcat directory for some lib folders (I cant remember the exact location and I think it changes based on the version) but something like ${CATALINE_HOME}/common/lib
Verify that he doesnt have differen JAR files in his tomcat installation as yours.
From this question: Does Tomcat load the same library file into memory twice if they are in two web apps?
They are apparently stored here:
Tomcat 6 $CATALINA_HOME/lib
Tomcat 5 $CATALINA_HOME/common/lib
I'm new to JavaFX. I have a JavaFX Application which is generating a jar and a JNLP file. As a DB I'm using SQLite db. The system runs fine when running it on Netbeans IDE but does not get going with built files (jnlp, jar). Problem is the JNLP is unable to find the db location when running with JNLP.
How can I fix it?
How is the DB installed?
Presuming the installer can accept an 'installation path', I would tend to:
Use an installer-desc element to start Java code.
That pops a JFileChooser to allow the user to create/select an installation directory
That it then passes (that path) to the DB installer, and..
Persists the path using the PersistenceService
When the main GUI starts, it can:
Read the DB path from the PersistenceService
Invoke/start the DB.
For demos. of some of the parts of that, see:
The PersistenceService.
The installer-desc that invokes the ExtensionInstallerService.
Sign your application to give it the permissions it needs to run correctly in jnlp mode.
If you have permissions on the machine you're running on and the user accepted them you should be able to write a new database file to the local system.
Make sure that you check that the database exists and if not create it. Failing that, what is the exception?
I use sqlite in my java application. When I run it from Netbeans, it works well. The sqlite db file is located in the root project directory (same level as build.xml).
This is the code to access the database file:
DriverManager.getConnection("jdbc:sqlite:database.db");
However, when I build the project, and run the jar file outside netbeans, I always get this error: no such table: table_name
My question: where is the correct location to put the "sqlite db" file? Is it possible to package it inside the JAR file?
I have tried to package my application into a single JAR file (similar to Eclipse's FatJar), but I still get that error. In this case I modify the build.xml as explained in this blog:
Netbeans single JAR
I also tried to create a database folder in the src directory and then put the db file inside the folder (src/database/database.db) and access it using
DriverManager.getConnection("jdbc:sqlite:src/database/database.db");
I can run it inside netbeans. But when I run it outside, I got this error:
path to 'src/database/database.db':C:\Windows\system32\src' does not exist
I know there are similar questions to this in stackoverflow, but most of them don't have a concrete solution. Let me know if someone has found a better one.
Thanks a lot.
Problem solved!
I made a mistake in the way I execute the JAR file. Previously I run the JAR file by right click on it and open it with Java SE binary. I need to do this because in my PC the default program to open JAR file was set to another software.
It turned out that I have to set the default program to Java SE Binary and the double click the JAR file in order to run my application. Using this way I can run and access the sqlite db file without a problem.
I hope this can help others who may get the same problem as I had.
probably you need to point your app to include your app base directory in the classpath.
the command to run your app should be something like:
java -cp . YourAppMainClass
the "-cp . " is the command option that tells java to include current directory in the classpath.