javap

 

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 javap(1)                                                 javap(1)
 
 
 
NAME
        javap - Java class file disassembler
 
SYNOPSIS
        javap [ -b ] [ -bootclasspath path ] [ -c ]
             [ -classpath path ] [ -extdirs dirs ] [ -help ]
             [ -J flag ] [ -l ] [ -package ] [ -private ]
             [ -protected ] [ -public ] [ -s ] [ -verbose ]
             class ...
 
DESCRIPTION
        The  javap  command disassembles a Javatm class file.  The
        options determine the output.  If  no  options  are  used,
        javap prints out the package, protected, and public fields
        and methods of the classes passed to it.  The  javap  com­
        mand  displays its output to stdout.  For example, compile
        the following class declaration:
 
               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 javap DocFooter yields:
 
               Compiled from DocFooter.java
               public class DocFooter extends java.applet.Applet {
                    java.lang.String date;
                    java.lang.String email;
                    public void init();
                    public void paint(java.awt.Graphics);
                    public DocFooter();
               }
 
 
OPTIONS
        The following options are supported:
 
        -b             Ensures backward compatibility  with  javap
                       in JDK 1.1.
 
        -bootclasspathpath
                       Specifies path from which to load bootstrap
                       classes.  By default, the bootstrap classes
                       are  the classes implementing the core Java
                       platform  located  in  jre/lib/rt.jar   and
                       jre/lib/i18n.jar.
 
        -c             Prints  out disassembled code, that is, the
                       instructions that comprise the  Java  byte­
                       codes,  for  each  of  the  methods  in the
                       class.  These are documented  in  the  Java
                       Virtual Machine Specification.
 
        -classpathpath Specifies  the  path  javap uses to look up
                       classes.   Overrides  the  default  or  the
                       CLASSPATH  environment  variable  if  it is
                       set.  Directories are separated  by  colons
                       (:).  Thus the general format for path is:
 
                            .:<your_path>
 
                       For example:
 
                            .:/home/avh/classes:/usr/local/java/classes
 
 
        -extdirsdirs   Overrides  location  at   which   installed
                       extensions are searched.  The default loca­
                       tion for extensions is jre/lib/ext.
 
        -help          Prints out help message for javap.
 
        -Jflag         Passes flag directly to runtime system.
 
                       example% javap -J-version
 
                       example%  javap  -JJ-Djava.security.manager
                       .br         -Djava.security.policy=MyPolicy
                       MyClassName
 
        -l             Displays line and local variable tables.
 
        -package       Default; shows only package, protected, and
                       public classes and members.
 
        -private       Shows all classes and members.
 
        -protected     Shows only protected and public classes and
                       members.
 
        -public        Shows only public classes and members.
 
        -s             Displays internal type signatures.
 
        -verbose       Prints stack size, number  of  locals,  and
                       args for methods.
 
ENVIRONMENT VARIABLES
        CLASSPATH      Used  to  provide the system with a path to
                       user-defined classes. Directories are sepa­
                       rated by colons.  For example:
 
                            .:/home/avh/classes:/usr/local/java/classes
 
 
 
 
 
 
 
 
 
SEE ALSO
        java(1), javac(1), javadoc(1), javah(1), jdb(1)
 
 
 
                            13 June 2000                  javap(1)

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