javap (original) (raw)

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."":()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."":()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
}