Does Java have a using statement?

Question

Does Java have a using statement that can be used when opening a session in hibernate?

In C# it is something like:

using (var session = new Session()         


        

Answer 1

If you're interested in resource management, Project Lombok offers the @Cleanup annotation. Taken directly from their site:

You can use @Cleanup to ensure a given resource is automatically cleaned up before the code execution path exits your current scope. You do this by annotating any local variable declaration with the @Cleanup annotation like so:

@Cleanup InputStream in = new FileInputStream("some/file");

As a result, at the end of the scope you're in, in.close() is called. This call is guaranteed to run by way of a try/finally construct. Look at the example below to see how this works.

If the type of object you'd like to cleanup does not have a close() method, but some other no-argument method, you can specify the name of this method like so:

@Cleanup("dispose") org.eclipse.swt.widgets.CoolBar bar = new CoolBar(parent, 0);

By default, the cleanup method is presumed to be close(). A cleanup method that takes argument cannot be called via @Cleanup.

Vanilla Java

import java.io.*;

public class CleanupExample {
  public static void main(String[] args) throws IOException {
    InputStream in = new FileInputStream(args[0]);
    try {
      OutputStream out = new FileOutputStream(args[1]);
      try {
        byte[] b = new byte[10000];
        while (true) {
          int r = in.read(b);
          if (r == -1) break;
          out.write(b, 0, r);
        }
      } finally {
        out.close();
      }
    } finally {
      in.close();
    }
  }
}

With Lombok

import lombok.Cleanup;
import java.io.*;

public class CleanupExample {
  public static void main(String[] args) throws IOException {
    @Cleanup InputStream in = new FileInputStream(args[0]);
    @Cleanup OutputStream out = new FileOutputStream(args[1]);
    byte[] b = new byte[10000];
    while (true) {
      int r = in.read(b);
      if (r == -1) break;
      out.write(b, 0, r);
    }
  }
}