Java 7 Developer Blog

c:\

Path target = Paths.get("D:\\Backup\\MyStuff.txt");
Path file = Files.createFile(target);

Path target = Paths.get("D:\\Backup\\MyStuff.txt");
Set<PosixFilePermission> perms
    = PosixFilePermissions.fromString("rw-rw-rw-");
FileAttribute<Set<PosixFilePermission>> attr
    = PosixFilePermissions.asFileAttribute(perms);
Files.createFile(target, attr);

Path target = Paths.get("D:\\Backup\\MyStuff.txt");
Files.delete(target);

Path source = Paths.get("C:\\My Documents\\Stuff.txt");
Path target = Paths.get("D:\\Backup\\MyStuff.txt");
Files.copy(source, target);

import static java.nio.file.StandardCopyOption.*;

Path source = Paths.get("C:\\My Documents\\Stuff.txt");
Path target = Paths.get("D:\\Backup\\MyStuff.txt");
Files.copy(source, target, REPLACE_EXISTING);

import static java.nio.file.StandardCopyOption.*;

Path source = Paths.get("C:\\My Documents\\Stuff.txt");
Path target = Paths.get("D:\\Backup\\MyStuff.txt");
Files.move(source, target, REPLACE_EXISTING, COPY_ATTRIBUTES);

package java.util.concurrent.locks;

public abstract class AutoLockable implements AutoCloseable
{
  public static AutoLockable locked(final Lock lock)
  {
    lock.lock();
    return new AutoLockable()
    {
      @Override
      public void close() {
        lock.unlock();
      }
    };
  }

  public abstract void close();
}

try(AutoLockable locked = AutoLockable.locked(lock))
{
  // Do something in locked scope
}

lock.lock();
try
{
  printLockStatus();
}
finally
{
  lock.unlock();
}

try (lock(lock))
{
  printLockStatus();
}

try(i < j // Ternary operator on variables i and j
                 ? new Resource1() :
                 new Resource2()) {...}

try(Box < Resource // Simple generic wrapper around a resource
 > resourceBox = Box<>(new Resource1())) {...}

public class TwrExamples implements AutoCloseable
{
  public static void main(String... args)
  {
    TwrExamples twrEg1 = new TwrExamples();
    System.out.println(twrEg1.hashCode());

    try(twrEg1)
    {
      twrEg1 = new TwrExamples();  // Mutating the variable!
      System.out.println(twrEg1.hashCode());
    }
  }

  @Override
  public void close()
  {
    System.out.println(hashCode());
  }
}

try (Resource r = getResource())
{
  /*.... */
}
catch (Exception e)
{
  icon = Icons.DEFAULT_ICON;
  logger.log("App icon resource " + r.getURL() + " is not available", e);
}

public class MethodAccessExampleWithArgs {
    private final int i;

    public MethodAccessExampleWithArgs(int i_) {
        i = i_;
    }

    private void bar(int j, String msg) {
        System.out.println("Private Method \'bar\' successfully accessed : "
                                          + i +", "+ j +" : "+ msg +"!");
    }

    // Using Reflection
    public static Method makeMethod() {
        Method meth = null;

        try {
            Class<?>[] argTypes =
                new Class[] { int.class, String.class };

            meth = MethodAccessExampleWithArgs.class.
                            getDeclaredMethod("bar", argTypes);

            meth.setAccessible(true);
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (SecurityException e) {
            e.printStackTrace();
        }

        return meth;
    }

    // Using method handles
    public static MethodHandle makeMh() {
        MethodHandle mh;

        MethodType desc = MethodType.methodType(void.class, int.class, String.class);

        try {
            mh = MethodHandles.lookup().findVirtual(MethodAccessExampleWithArgs.class, "bar", desc);
            System.out.println("mh="+mh);
        } catch (NoAccessException e) {
            throw (AssertionError)new AssertionError().initCause(e);
        }
        return mh;
      }
  }

public class MethodAccessMain {

    private static void withReflectionArgs() {
        Method meth = MethodAccessExampleWithArgs.makeMethod();

        MethodAccessExampleWithArgs mh0 =
            new MethodAccessExampleWithArgs(0);
        MethodAccessExampleWithArgs mh1 =
            new MethodAccessExampleWithArgs(1);

        try {
            System.out.println("Invocation using Reflection");
            meth.invoke(mh0, 5, "Jabba the Hutt");
            meth.invoke(mh1, 7, "Boba Fett");
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }

    private static void withMhArgs() {
        MethodHandle mh = MethodAccessExampleWithArgs.makeMh();

        MethodAccessExampleWithArgs mh0 =
            new MethodAccessExampleWithArgs(0);
        MethodAccessExampleWithArgs mh1 =
            new MethodAccessExampleWithArgs(1);

        try {
            System.out.println("Invocation using Method Handle");
            mh.invokeExact(mh0, 42, "R2D2");
            mh.invokeExact(mh1, 43, "C3PO");
        } catch (Throwable e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        withReflectionArgs();
        withMhArgs();
    }
}

run:
Invocation using Reflection
Private Method 'bar' successfully accessed : 0, 5 : Jabba the Hutt!
Private Method 'bar' successfully accessed : 1, 7 : Boba Fett!

java.dyn.WrongMethodTypeException: (ILjava/lang/String;)V cannot be called as ([Ljava/lang/Object;)Ljava/lang/Object;
mh=bar(MethodAccessExampleWithArgs,int,String)void
Invocation using Method Handle
    at ben.example.MethodAccessMain.withMhArgs(MethodAccessMain.java:46)
    at ben.example.MethodAccessMain.main(MethodAccessMain.java:55)

BUILD SUCCESSFUL (total time: 0 seconds)

Java 7 Developer Blog

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Copying and Moving files

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Ben and Martijn are interviewed at Javaworld

Some insights from Oracle on the their plans for Java

Official Java 7 for Mac OS X – Status

Project Coin: the try-with-resources lock support debate

Conservativism in Language Design

A glimpse at MethodHandle and its usage

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