TIP
Decompile the specified classes.
jad helps to decompile the byte code running in JVM to the source code to assist you to understand the logic behind better.
| Name | Specification |
|---|---|
| class-pattern | pattern for the class name |
[c:] | hashcode of the class loader that loads the class |
[classLoaderClass:] | The class name of the ClassLoader that executes the expression. |
[E] | turn on regex match while the default is wildcard match |
java.lang.String$ jad java.lang.String
ClassLoader:
Location:
/*
* Decompiled with CFR.
*/
package java.lang;
import java.io.ObjectStreamField;
import java.io.Serializable;
...
public final class String
implements Serializable,
Comparable<String>,
CharSequence {
private final char[] value;
private int hash;
private static final long serialVersionUID = -6849794470754667710L;
private static final ObjectStreamField[] serialPersistentFields = new ObjectStreamField[0];
public static final Comparator<String> CASE_INSENSITIVE_ORDER = new CaseInsensitiveComparator();
...
public String(byte[] byArray, int n, int n2, Charset charset) {
/*460*/ if (charset == null) {
throw new NullPointerException("charset");
}
/*462*/ String.checkBounds(byArray, n, n2);
/*463*/ this.value = StringCoding.decode(charset, byArray, n, n2);
}
...
$ jad --source-only demo.MathGame
/*
* Decompiled with CFR 0_132.
*/
package demo;
import java.io.PrintStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import java.util.concurrent.TimeUnit;
public class MathGame {
private static Random random = new Random();
public int illegalArgumentCount = 0;
...
$ jad demo.MathGame main
ClassLoader:
+-sun.misc.Launcher$AppClassLoader@232204a1
+-sun.misc.Launcher$ExtClassLoader@7f31245a
Location:
/private/tmp/math-game.jar
public static void main(String[] args) throws InterruptedException {
MathGame game = new MathGame();
while (true) {
/*16*/ game.run();
/*17*/ TimeUnit.SECONDS.sleep(1L);
}
}
--lineNumber: Output source code contins line numbers, default value true$ jad demo.MathGame main --lineNumber false
ClassLoader:
+-sun.misc.Launcher$AppClassLoader@232204a1
+-sun.misc.Launcher$ExtClassLoader@7f31245a
Location:
/private/tmp/math-game.jar
public static void main(String[] args) throws InterruptedException {
MathGame game = new MathGame();
while (true) {
game.run();
TimeUnit.SECONDS.sleep(1L);
}
}
TIP
If the target class is loaded by multiple classloaders, jad outputs the hashcode of the corresponding classloaders, then you can re-run jad and specify -c <hashcode> to decompile the target class from the specified classloader.
$ jad org.apache.log4j.Logger
Found more than one class for: org.apache.log4j.Logger, Please use jad -c hashcode org.apache.log4j.Logger
HASHCODE CLASSLOADER
69dcaba4 +-monitor's ModuleClassLoader
6e51ad67 +-java.net.URLClassLoader@6e51ad67
+-sun.misc.Launcher$AppClassLoader@6951a712
+-sun.misc.Launcher$ExtClassLoader@6fafc4c2
2bdd9114 +-pandora-qos-service's ModuleClassLoader
4c0df5f8 +-pandora-framework's ModuleClassLoader
Affect(row-cnt:0) cost in 38 ms.
$ jad org.apache.log4j.Logger -c 69dcaba4
ClassLoader:
+-monitor's ModuleClassLoader
Location:
/Users/admin/app/log4j-1.2.14.jar
package org.apache.log4j;
import org.apache.log4j.spi.*;
public class Logger extends Category
{
private static final String FQCN;
protected Logger(String name)
{
super(name);
}
...
Affect(row-cnt:1) cost in 190 ms.
For classloader with only one instance, it can be specified by --classLoaderClass using class name, which is more convenient to use.
The value of --classloaderclass is the class name of classloader. It can only work when it matches a unique classloader instance. The purpose is to facilitate the input of general commands. However, -c <hashcode> is dynamic.