javap-java-1.8.0-openjdk-1.8.0.91-0.b14.el6_7.i386

javap(1)                          Basic Tools                         javap(1)



NAME
       javap - Disassembles one or more class files.

SYNOPSIS
           javap [options] classfile...

       options
           The command-line options. See Options.

       classfile
           One or more classes separated by spaces to be processed for
           annotations such as DocFooter.class. You can specify a class that
           can be found in the class path, by its file name or with a URL such
           as file:///home/user/myproject/src/DocFooter.class.

DESCRIPTION
       The javap command disassembles one or more class files. The output
       depends on the options used. When no options are used, then the javap
       command prints the package, protected and public fields, and methods of
       the classes passed to it. The javap command prints its output to
       stdout.

OPTIONS
       -help
       --help
       -?
           Prints a help message for the javap command.

       -version
           Prints release information.

       -l
           Prints line and local variable tables.

       -public
           Shows only public classes and members.

       -protected
           Shows only protected and public classes and members.

       -private
       -p
           Shows all classes and members.

       -Joption
           Passes the specified option to the JVM. For example:

               javap -J-version
               javap -J-Djava.security.manager -J-Djava.security.policy=MyPolicy MyClassName

           For more information about JVM options, see the command
           documentation.

       -s
           Prints internal type signatures.

       -sysinfo
           Shows system information (path, size, date, MD5 hash) of the class
           being processed.

       -constants
           Shows static final constants.

       -c
           Prints disassembled code, for example, the instructions that
           comprise the Java bytecodes, for each of the methods in the class.

       -verbose
           Prints stack size, number of locals and arguments for methods.

       -classpath path
           Specifies the path the javap command uses to look up classes.
           Overrides the default or the CLASSPATH environment variable when it
           is set.

       -bootclasspath path
           Specifies the path from which to load bootstrap classes. By
           default, the bootstrap classes are the classes that implement the
           core Java platform located in jre/lib/rt.jar and several other JAR
           files.

       -extdir dirs
           Overrides the location at which installed extensions are searched
           for. The default location for extensions is the value of
           java.ext.dirs.

EXAMPLE
       Compile the following DocFooter class:

           import java.awt.*;
           import java.applet.*;

           public class DocFooter extends Applet {
                   String date;
                   String email;

                   public void init() {
                           resize(500,100);
                           date = getParameter("LAST_UPDATED");
                           email = getParameter("EMAIL");
                   }

                   public void paint(Graphics g) {
                           g.drawString(date + " by ",100, 15);
                           g.drawString(email,290,15);
                   }
           }


       The output from the javap DocFooter.class command yields the following:

           Compiled from "DocFooter.java"
           public class DocFooter extends java.applet.Applet {
             java.lang.String date;
             java.lang.String email;
             public DocFooter();
             public void init();
             public void paint(java.awt.Graphics);
           }


       The output from javap -c DocFooter.class command yields the following:

           Compiled from "DocFooter.java"
           public class DocFooter extends java.applet.Applet {
             java.lang.String date;
             java.lang.String email;

             public DocFooter();
               Code:
                  0: aload_0
                  1: invokespecial #1                  // Method
           java/applet/Applet."<init>":()V
                  4: return

             public void init();
               Code:
                  0: aload_0
                  1: sipush        500
                  4: bipush        100
                  6: invokevirtual #2                  // Method resize:(II)V
                  9: aload_0
                 10: aload_0
                 11: ldc           #3                  // String LAST_UPDATED
                 13: invokevirtual #4                  // Method
            getParameter:(Ljava/lang/String;)Ljava/lang/String;
                 16: putfield      #5                  // Field date:Ljava/lang/String;
                 19: aload_0
                 20: aload_0
                 21: ldc           #6                  // String EMAIL
                 23: invokevirtual #4                  // Method
            getParameter:(Ljava/lang/String;)Ljava/lang/String;
                 26: putfield      #7                  // Field email:Ljava/lang/String;
                 29: return

             public void paint(java.awt.Graphics);
               Code:
                  0: aload_1
                  1: new           #8                  // class java/lang/StringBuilder
                  4: dup
                  5: invokespecial #9                  // Method
            java/lang/StringBuilder."<init>":()V
                  8: aload_0
                  9: getfield      #5                  // Field date:Ljava/lang/String;
                 12: invokevirtual #10                 // Method
            java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
                 15: ldc           #11                 // String  by
                 17: invokevirtual #10                 // Method
            java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
                 20: invokevirtual #12                 // Method
            java/lang/StringBuilder.toString:()Ljava/lang/String;
                 23: bipush        100
                 25: bipush        15
                 27: invokevirtual #13                 // Method
            java/awt/Graphics.drawString:(Ljava/lang/String;II)V
                 30: aload_1
                 31: aload_0
                 32: getfield      #7                  // Field email:Ljava/lang/String;
                 35: sipush        290
                 38: bipush        15
                 40: invokevirtual #13                 // Method
           java/awt/Graphics.drawString:(Ljava/lang/String;II)V
                 43: return
           }


SEE ALSO
       ·   java(1)

       ·   javac(1)

       ·   javadoc(1)

       ·   javah(1)

       ·   jdb(1)

       ·   jdeps(1)



JDK 8                            8 August 2014                        javap(1)