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try catch vs try-with-resources

Why in the readFile2() I need to catch the FileNotFoundException and later the IOException that is thrown by the close() method, and in the try-with-resources(inside readfile1) Java doesn't ask me to handle the FileNotFoundException, what happened?
public class TryWithResourcesTest {
public static void main(String[] args) {
}
public static void readFile1() {
try(Reader reader = new BufferedReader(new FileReader("text.txt"))) {
} catch (IOException e) {
e.printStackTrace();
}
}
public static void readFile2() {
Reader reader = null;
try {
reader = new BufferedReader(new FileReader("text.txt"));
} catch (FileNotFoundException e) {
e.printStackTrace();
} finally {
try {
if(reader != null)
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}

FileNotFoundException is a subclass of IOException. By catching the latter, you're catching the former too. It has nothing to do with try-catch vs. try-with-resources.

How to close a RandomAccessFile

I'm trying to close a RandomAccessFile but resource remain busy.
Code:
public boolean isOpen(RandomAccessFile f) {
try {
f.length() ;
return true ;
}
catch (IOException e) {
return false ;
}
}
this.rfmFile = new File(filePath);
try {
this.rfmRandomAccessFile = new RandomAccessFile(rfmFile, "rws");
} catch(Exception e){
}finally{
this.rfmRandomAccessFile.close();
}
while(!isOpen(this.rfmRandomAccessFile));
log.debug("I Finally Closed this RAF");
Log is not showed and thread goes in loop.
When I try to access to my resource from shell it gives me "Device or Resource busy".
The only way to access is kill java process.

When you are trying to access the RandomAccessFile length(), method, it is already closed and thus you cannot access it anymore.
You probably want to use the length() method of File. Your loop cannot work as the RandomAccessFile was already closed.
But I must admit I am clueless on the low level reason why rfmRandomAccessFile would not really be closed. It could be a side effect of your strange loop trying to get the size of a closed file.
[edit:]Could not reproduce your issue with the following piece of code:
package com.company;
import java.io.*;
public class Main {
public static void main(String[] args) {
File file = new File("foobar.txt");
RandomAccessFile randomAccessFile = null;
try {
randomAccessFile = new RandomAccessFile(file, "rws");
randomAccessFile.write(new byte[]{'f'});
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if(randomAccessFile !=null){
try {
randomAccessFile.close();
} catch (IOException e) {
//doh!
}
}
}
FileReader reader = null;
try {
reader = new FileReader(file);
char read = (char) reader.read();
System.out.println("what was written: "+read);
System.out.println("file size: "+file.length());
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if(reader !=null){
try {
reader.close();
} catch (IOException e) {
//doh!
}
}
}
}
}

Repeatedly Writing to a File

I'm a moderately-experienced C++ guy slowly learning Java. I'm writing a program which needs to do the following:
Create a simple text file, default directory is fine
As the program runs, periodically write one line of data to the file. Depending on a number of factors, the program may write to the file once or a million times. There is no way of knowing which write will be the last.
I've been researching different ways to do this, and this is the working code I've come up with. There are two files, "PeteProgram.java" and "PeteFileMgr.java" :
/*
"PeteProgram.java"
*/
import java.io.*;
import java.lang.String;
public class PeteProgram {
public static void main(String[] args) throws IOException {
String PeteFilename="MyRecordsFile.txt";
Writer writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(PeteFilename), "utf-8"));
PeteFileMgr MyPeteFileMgr = new PeteFileMgr(writer);
MyPeteFileMgr.AddThisString(writer, "Add this line #1\n");
MyPeteFileMgr.AddThisString(writer, "Add this line #2\n");
MyPeteFileMgr.AddThisString(writer, "Add this line #3\n");
}
}
//=====================================================================================================
//=====================================================================================================
/*
"PeteFileMgr.java"
*/
import java.io.*;
public class PeteFileMgr {
public PeteFileMgr(Writer writer) {
try {
writer.write("File created!");
} catch (IOException ex) {
// report
} finally {
try {writer.close();} catch (Exception ex) {}
}
}
void AddThisString(Writer writer, String AddThis) {
try {
writer.append(AddThis);
} catch (IOException ex) {
// report
} finally {
try {writer.close();} catch (Exception ex) {}
}
}
}
The initial creation of the file works just fine. However, the to-be-added lines are not written into the file. Because the program compiles and runs with no errors, I assume the program tries to write the added lines, fails, and throws an exception. (Unfortunately, I am working with a primitive compiler/debugger and can't see if this is the case.)
Does anyone spot my mistake?
Many thanks!
-P

That's because you're not flushing the Writer. You should call flush from time to time. Also, you should close your Writer at the end of your app, not after writing content into it. close method automatically flushes the contents of the writer.
So, this is how your code should look like:
public class PeteProgram {
public static void main(String[] args) {
String peteFilename = "MyRecordsFile.txt";
//here's when the physical file is created
Writer writer = null;
try {
writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(peteFilename), "utf-8"));
PeteFileMgr peteFileMgr = new PeteFileMgr(writer);
peteFileMgr.addThisString(writer, "Add this line #1\n");
peteFileMgr.addThisString(writer, "Add this line #2\n");
peteFileMgr.addThisString(writer, "Add this line #3\n");
} catch (IOException e) {
//handle the exception
//basic handling
e.printStacktrace();
} finally {
//this is a must!
try { writer.close(); } catch(IOException silent) { }
}
}
}
public class PeteFileMgr {
public PeteFileMgr(Writer writer) {
try {
//this method is not creating the physical file
writer.write("File created!");
} catch (IOException ex) {
// report
} finally {
//remove this call to close
//try {writer.close();} catch (Exception ex) {}
}
}
public void addThisString(Writer writer, String addThis) {
try {
writer.append(addThis);
} catch (IOException ex) {
// report
} finally {
//remove this call to close
//try {writer.close();} catch (Exception ex) {}
}
}
}
Or if using Java 7 or superior using the try-with-resources:
public class PeteProgram {
public static void main(String[] args) {
String peteFilename = "MyRecordsFile.txt";
//here's when the physical file is created
try (Writer writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(peteFilename), "utf-8"))) {
PeteFileMgr peteFileMgr = new PeteFileMgr(writer);
peteFileMgr.addThisString(writer, "Add this line #1\n");
peteFileMgr.addThisString(writer, "Add this line #2\n");
peteFileMgr.addThisString(writer, "Add this line #3\n");
} catch (IOException e) {
//handle the exception
//basic handling
e.printStacktrace();
}
}
}

Output text to a file with a class method java

I have a valet class method that should write an hourly wage to a file:
public void hourlyOverall() throws FileNotFoundException
{
PrintWriter out = new PrintWriter("wage info");
new FileOutputStream("wage info", true);
hourlyOverall = tips / hours + hourlyWage;
out.println(hourlyOverall);
}
However, when I run valet.hourlyOverall() in my main method, the file "wage info" is created but nothing is written to it. What am I doing wrong?

First of all use try-catch for Exception handling and then in the finally block close the OutputStream
out.flush();
Somthing like this
try {
PrintWriter out = new PrintWriter("wage info");
hourlyOverall=tips/hours+hourlyWage;
out.println(hourlyOverall);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
finally {
out.flush();
}

I think this is another way to solve your problem, but using another classes
public class valet {
public static void main(String []args)throws IOException
{
try
{
hourlyOverall()
}
catch(IOException ex)
{
System.out.println(ex+"\n");
}
}
public void hourlyOverall() throws IOException
{
FileWriter out = new FileWriter("wage info");
hourlyOverall=tips/hours+hourlyWage;
out.write(hourlyOverall+"\r\n");
out.close();
}
}

You probably shouldn't declare an anonymous FileOutputStream and you should probably close your PrintWriter,
PrintWriter out=new PrintWriter("wage info");
// new FileOutputStream("wage info",true);
hourlyOverall=tips/hours+hourlyWage;
out.println(hourlyOverall);
out.close(); // <-- like that

Do something like this (if java7 or above) :
public void hourlyOverall()
{
try (PrintWriter out=new PrintWriter("wage info")){
//new FileOutputStream("wage info",true);
hourlyOverall=tips/hours+hourlyWage;
out.println(hourlyOverall);
}catch (FileNotFoundException e) {
e.printStackTrace();
}
}
http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html

How do I close this file writer? (Java, Bukkit)

try {
FileWriter fw = new FileWriter("plugins/TestMessage/messages.txt", true);
} catch (IOException e) {
e.printStackTrace();}
}
Hey guys, I know this may sound noobish but how do I close this FileWriter. The code is in java. I have an onDisable() method that gets called when the server is stopped but when I put fw.close(); It says fw cannot be resolved. Please help!
The relevant section of the code is
public class MAIN extends JavaPlugin{{
try {
FileWriter fw = new FileWriter("plugins/TestMessage/messages.txt", true);
} catch (IOException e) {
e.printStackTrace();}
}
public void onEnable(){
Logger.getLogger("Minecraft").info("MessageBroadcaster made by cheeseballs500 aka weakwizardsucks2");
}
public void onDisable(){
fw.close();//fw cannot be resolved
}
EDIT: Fixed :D

Try creating the FileWriter outside of any methods, then setting it to something in your onEnable()... Here's an example:
public class Main extends JavaPlugin{{
FileWriter fw;//create the variable
#Override
public void onEnable(){
try{
fw = new FileWriter(this.getDataFolder() + "/messages.txt", true); //assign the variable to a value, and put the file in your plugin's folder
}
catch(IOException e){
e.printStackTrace();
}
}
#Override
public void onDisable(){
try{ //try-catch just incase
fw.close();
}
catch(Exception e){
e.printStackTrace();
}
}
}

Try this..
public class MAIN extends JavaPlugin{
public MAIN() {
try {
this.fw = new FileWriter("plugins/TestMessage/messages.txt", true);
} catch (Exception e) {
// TODO: handle exception
}
}
FileWriter fw = null;
public void onEnable(){
Logger.getLogger("Minecraft").info("MessageBroadcaster made by cheeseballs500 aka weakwizardsucks2");
}
public void onDisable(){
try {
fw.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}//fw cannot be resolved
}
}