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public class HelloWorld {
public HelloWorld () {
System.out.println("Hello World!");
}
public static void main(final String[] args) {
HelloWorld hw = new HelloWorld();
}
}
<?xml version="1.0" encoding="UTF-8"?>
<project name="HelloWorld" default="dist" basedir=".">
<description>
Build file for the HelloWorld program.
</description>
<!-- set global properties for this build -->
<property name="src" value="."/>
<property name="build" value="build"/>
<property name="jarfile" value="HelloWorld.jar"/>
<target name="dist" description="Build the Java source files, and generate the jar file." >
<!-- Create the necessary directory structure -->
<mkdir dir="${build}"/>
<!-- Create the time stamp -->
<tstamp/>
<!-- Compile the java code -->
<javac srcdir="${src}" destdir="${build}" includeantruntime="false">
<compilerarg value="-Xlint:unchecked,deprecation"/>
</javac>
<!-- Create the jar file -->
<jar jarfile="${jarfile}" basedir="${build}">
<manifest>
<attribute name="Main-Class" value="HelloWorld"/>
</manifest>
</jar>
</target>
<target name="clean" description="Clean up." >
<!-- Delete the ${build} directory tree -->
<delete dir="${build}"/>
<delete file="${jarfile}"/>
</target>
</project>
$ uname -a Linux whitney 3.8.0-30-generic #44-Ubuntu SMP Thu Aug 22 20:52:24 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux $ java -version java version "1.7.0_25" OpenJDK Runtime Environment (IcedTea 2.3.10) (7u25-2.3.10-1ubuntu0.13.04.2) OpenJDK 64-Bit Server VM (build 23.7-b01, mixed mode) $ ant Buildfile: build.xml dist: BUILD SUCCESSFUL Total time: 0 seconds $ /usr/bin/time --verbose java -Xshare:on -jar HelloWorld.jar Hello World! Command being timed: "java -Xshare:on -jar HelloWorld.jar" User time (seconds): 0.05 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.07 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 17772 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5124 Voluntary context switches: 75 Involuntary context switches: 11 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0
import java.awt.BorderLayout;
import java.awt.event.WindowEvent;
import java.awt.event.WindowAdapter;
import javax.swing.JFrame;
import javax.swing.JTextArea;
public class HelloWorld {
public HelloWorld () {
JFrame gui = new JFrame();
JTextArea textArea = new JTextArea();
textArea.setColumns(20);
textArea.setRows(5);
textArea.append("Hello World");
gui.setTitle("Hello World");
gui.add(textArea, BorderLayout.CENTER);
gui.pack();
gui.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
System.exit(0);
}
});
gui.setVisible(true);
}
public static void main(final String[] args) {
HelloWorld hw = new HelloWorld();
}
}
$ /usr/bin/time --verbose java -Xshare:on -jar HelloWorld.jar Command being timed: "java -Xshare:on -jar HelloWorld.jar" User time (seconds): 0.51 System time (seconds): 0.07 Percent of CPU this job got: 15% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:03.83 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 43256 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 12993 Voluntary context switches: 561 Involuntary context switches: 94 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0
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