Java class decompiled: HelloWorld.class

Mobilefish.com Online Java Class Decompiler

Author: Robert Lie
Version: 0.1 (pre-alpha)
https://www.mobilefish.com/services/java_decompiler/java_decompiler.php

More information about the Java class file format can be found at:
https://www.mobilefish.com/tutorials/java/java_quickguide_classfile.html

Analysis report of HelloWorld.class

Generated at Sun, 14 Feb 2010 10:16:59 +0100

Class file structure

	0	1	2	3	4	5	6	7	8	9	a	b	c	d	e	f
0	ca	fe	ba	be	00	00	00	32	00	22	07	00	02	01	00	1e
10	63	6f	6d	2f	6d	6f	62	69	6c	65	66	69	73	68	2f	74
20	65	73	74	2f	48	65	6c	6c	6f	57	6f	72	6c	64	07	00
30	04	01	00	10	6a	61	76	61	2f	6c	61	6e	67	2f	4f	62
40	6a	65	63	74	01	00	06	3c	69	6e	69	74	3e	01	00	03
50	28	29	56	01	00	04	43	6f	64	65	0a	00	03	00	09	0c
60	00	05	00	06	01	00	0f	4c	69	6e	65	4e	75	6d	62	65
70	72	54	61	62	6c	65	01	00	12	4c	6f	63	61	6c	56	61
80	72	69	61	62	6c	65	54	61	62	6c	65	01	00	04	74	68
90	69	73	01	00	20	4c	63	6f	6d	2f	6d	6f	62	69	6c	65
a0	66	69	73	68	2f	74	65	73	74	2f	48	65	6c	6c	6f	57
b0	6f	72	6c	64	3b	01	00	04	6d	61	69	6e	01	00	16	28
c0	5b	4c	6a	61	76	61	2f	6c	61	6e	67	2f	53	74	72	69
d0	6e	67	3b	29	56	09	00	11	00	13	07	00	12	01	00	10
e0	6a	61	76	61	2f	6c	61	6e	67	2f	53	79	73	74	65	6d
f0	0c	00	14	00	15	01	00	03	6f	75	74	01	00	15	4c	6a
100	61	76	61	2f	69	6f	2f	50	72	69	6e	74	53	74	72	65
110	61	6d	3b	08	00	17	01	00	27	48	65	6c	6c	6f	20	77
120	6f	72	6c	64	2c	20	77	65	6c	63	6f	6d	65	20	74	6f
130	20	4d	6f	62	69	6c	65	66	69	73	68	2e	63	6f	6d	2e
140	0a	00	19	00	1b	07	00	1a	01	00	13	6a	61	76	61	2f
150	69	6f	2f	50	72	69	6e	74	53	74	72	65	61	6d	0c	00
160	1c	00	1d	01	00	07	70	72	69	6e	74	6c	6e	01	00	15
170	28	4c	6a	61	76	61	2f	6c	61	6e	67	2f	53	74	72	69
180	6e	67	3b	29	56	01	00	04	61	72	67	73	01	00	13	5b
190	4c	6a	61	76	61	2f	6c	61	6e	67	2f	53	74	72	69	6e
1a0	67	3b	01	00	0a	53	6f	75	72	63	65	46	69	6c	65	01
1b0	00	0f	48	65	6c	6c	6f	57	6f	72	6c	64	2e	6a	61	76
1c0	61	00	21	00	01	00	03	00	00	00	00	00	02	00	01	00
1d0	05	00	06	00	01	00	07	00	00	00	2f	00	01	00	01	00
1e0	00	00	05	2a	b7	00	08	b1	00	00	00	02	00	0a	00	00
1f0	00	06	00	01	00	00	00	03	00	0b	00	00	00	0c	00	01
200	00	00	00	05	00	0c	00	0d	00	00	00	09	00	0e	00	0f
210	00	01	00	07	00	00	00	37	00	02	00	01	00	00	00	09
220	b2	00	10	12	16	b6	00	18	b1	00	00	00	02	00	0a	00
230	00	00	0a	00	02	00	00	00	05	00	08	00	06	00	0b	00
240	00	00	0c	00	01	00	00	00	09	00	1e	00	1f	00	00	00
250	01	00	20	00	00	00	02	00	21

Class file overview

Byte index range	Description	Value	Remark
00-03	magic (u4)	cafebabe	The magic number is common to all Java class files.
04-05	minor version (u2)	0	Minor and Major versions are version numbers of the compiler that created the class file.
06-07	major version (u2)	50	Minor and Major versions are version numbers of the compiler that created the class file. Class file (Major.minor) version = 50.0 The class file is compiled by JVM 1.6 (Java SE 6) and is supported by JVM 1.7 (Java SE 7)
08-09	constant pool count (u2)	34	Constant pool count is the number of entries in the constant pool table.
0a -1c0	constant pool	See Constant Pool Table	Constant pool is a table of variable length entries defined by a leading tag byte followed by data. The constant pool holds Strings, numeric values, class references, method references, and so on.
1c1-1c2	access flags (u2)	public	Access flags are modifiers used for the class or interface (such as public, final, and the like).
1c3-1c4	this class (u2)	com.mobilefish.test.HelloWorld	This class is an index into the constant pool (pointing to type CONSTANT_Class), which represents the class or interface defined by this class file.
1c5-1c6	super class (u2)	java.lang.Object	Super class is an index into the constant pool (pointing to type CONSTANT_Class), which represents the superclass of this class. The only exception is java.lang.Object whose superclass index is 0.
1c7-1c8	interfaces count (u2)	0	Interface count is the number of entries in the interface table.
	interfaces info	Not available
1c9-1ca	fields count (u2)	0	Field count is the number of entries in the field table.
	fields info	Not available
1cb-1cc	methods count (u2)	2	Method count is the number of entries in the method table.
1cd-24e	methods info	See Methods, Methods attributes and Code atributes table below	Method info is an array of variable-length entries representing each method defined (not inherited) by this class.
24f-250	attributes count (u2)	1	Attribute count is the number of entries in the attribute table.
251-258	attributes info	See Class attributes table below	Attribute info is an array of variable-length entries representing each attribute of this class. Attributes give additional information about the class, such as the source file.

Constant Pool Table

CP Index	Byte index range	Tag (u1)	Constant Type	Value (*1)	Ref1 (*2)	Ref2 (*3)	Class or String	Name	Type
0	The constant pool index always start with index 0 but the entry is not included in the class file
1	a-c	7	Class Ref		2		com.mobilefish.test.HelloWorld
2	d-2d	1	UTF8	com/mobilefish/test/HelloWorld
3	2e-30	7	Class Ref		4		java.lang.Object
4	31-43	1	UTF8	java/lang/Object
5	44-4c	1	UTF8	<init>
6	4d-52	1	UTF8	()V
7	53-59	1	UTF8	Code
8	5a-5e	10	Method Ref		3	9	java.lang.Object	<init>	()V
9	5f-63	12	Name and Type		5	6		<init>	()V
10	64-75	1	UTF8	LineNumberTable
11	76-8a	1	UTF8	LocalVariableTable
12	8b-91	1	UTF8	this
13	92-b4	1	UTF8	Lcom/mobilefish/test/HelloWorld;
14	b5-bb	1	UTF8	main
15	bc-d4	1	UTF8	([Ljava/lang/String;)V
16	d5-d9	9	Field Ref		17	19	java.lang.System	out	Ljava.io.PrintStream;
17	da-dc	7	Class Ref		18		java.lang.System
18	dd-ef	1	UTF8	java/lang/System
19	f0-f4	12	Name and Type		20	21		out	Ljava.io.PrintStream;
20	f5-fa	1	UTF8	out
21	fb-112	1	UTF8	Ljava/io/PrintStream;
22	113-115	8	String Ref		23		Hello world, welcome to Mobilefish.com.
23	116-13f	1	UTF8	Hello world, welcome to Mobilefish.com.
24	140-144	10	Method Ref		25	27	java.io.PrintStream	println	(Ljava.lang.String;)V
25	145-147	7	Class Ref		26		java.io.PrintStream
26	148-15d	1	UTF8	java/io/PrintStream
27	15e-162	12	Name and Type		28	29		println	(Ljava.lang.String;)V
28	163-16c	1	UTF8	println
29	16d-184	1	UTF8	(Ljava/lang/String;)V
30	185-18b	1	UTF8	args
31	18c-1a1	1	UTF8	[Ljava/lang/String;
32	1a2-1ae	1	UTF8	SourceFile
33	1af-1c0	1	UTF8	HelloWorld.java

(*1)
If Constant type is UTF8, the value consist of a variable number of bytes (uN).
The number of bytes is determined by the 2 bytes (u2) following the tag byte (u1).
If Constant type is Integer, the value consist of a 4 bytes (u4).
If Constant type is Float, the value consist of a 4 bytes (u4).
If Constant type is Long, the value consist of a 8 bytes (u8).
If Constant type is Double, the value consist of a 8 bytes (u8).

(*2)
If Constant type is Class Ref, a reference to UTF8 is found in Ref1 (u2).
If Constant type is String Ref, a reference to UTF8 is found in Ref1 (u2).
If Constant type is Field Ref, a reference to Class Ref is found in Ref1 (u2).
If Constant type is Method Ref, a reference to Class Ref is found in Ref1 (u2).
If Constant type is Interface Method Ref, a reference to Class Ref is found in Ref1 (u2).
If Constant type is Name and Type, a reference to UTF8 is found in Ref1 (u2).

(*3)
If Constant type is Field Ref, a reference to Name and Type is found in Ref2 (u2).
If Constant type is Method Ref, a reference to Name and Type is found in Ref2 (u2).
If Constant type is Interface Method Ref, a reference to Name and Type is found in Ref2 (u2).
If Constant type is Name and Type, a reference to UTF8 is found in Ref2 (u2).

Interfaces

Not available

Fields

Not available

Field attributes

Not available

Methods

Index	Byte index range	Access Flag (u2)	Name (u2)	Descriptor (u2)	Attributes count (u2)
0	1cd-1d4	public	<init>	()V	1
1	20a-211	public static	main	([Ljava/lang/String;)V	1

Method attributes

Index	Ref to Methods index	Byte index range	Name (u2)	Attribute length (u4)
0	0	1d5-1da	Code	47
1	1	212-217	Code	55

Code attributes

Index	Ref to Method attributes index	Byte index range	max stack (u2) (maximum size of the operand stack)	max locals (u2) (maximum number of local variables allocated for this method)	code length (u4)	code array (*1)	exception table length (u2)	exception array (*2)	attributes count (u2)
0	0	1db-1eb	1	1	5	2a b7 00 08 b1	0		2
1	1	218-22c	2	1	9	b2 00 10 12 16 b6 00 18 b1	0		2

(*1)
The code length determines the number of records in the code array.
Each code array record is 1 byte in size.

(*2)
The exception table length determines the number of records in the exception array.
Each record in the exception array contains the following values:
start_pc (u2)
end_pc (u2)
handler_pc (u2)
catch_type_index (u2)

LineNumber table

#	Ref to Code attributes index	Byte index range	line number table length (u2)	start pc (u2)	linenumber (u2)
0	0	1f2-1f7	1	0	3
1	1	233-23c	2	0 8	5 6

The table will only be displayed if you compile with the following options:

javac -g:lines <source files> or javac -g <source files>

LocalVariable table

#	Ref to Code attributes index	Byte index range	localvariable table length (u2)	start pc (u2)	length (u2)	name index (u2)	descriptor index (u2)	index (u2)	name (*1)	descriptor (*2)
0	0	1fe-209	1	0	5	12	13	0	this	Lcom/mobilefish/test/HelloWorld;
1	1	243-24e	1	0	9	30	31	0	args	[Ljava/lang/String;

(*1)
The value is retrieved from the Constant Pool Table based on the name index value.

(*2)
The value is retrieved from the Constant Pool Table based on the descriptor index value.

The table will only be displayed if you compile with the following options:

javac -g:vars <source files> or javac -g <source files>

Class attributes

#	Byte index range	Name (u2)	Attribute length (u2)	Value (*1)
0	251-258	SourceFile	2	value (u2)=HelloWorld.java

	0	1	2	3	4	5	6	7	8	9	a	b	c	d	e	f
0	ca	fe	ba	be	00	00	00	32	00	22	07	00	02	01	00	1e
10	63	6f	6d	2f	6d	6f	62	69	6c	65	66	69	73	68	2f	74
20	65	73	74	2f	48	65	6c	6c	6f	57	6f	72	6c	64	07	00
30	04	01	00	10	6a	61	76	61	2f	6c	61	6e	67	2f	4f	62
40	6a	65	63	74	01	00	06	3c	69	6e	69	74	3e	01	00	03
50	28	29	56	01	00	04	43	6f	64	65	0a	00	03	00	09	0c
60	00	05	00	06	01	00	0f	4c	69	6e	65	4e	75	6d	62	65
70	72	54	61	62	6c	65	01	00	12	4c	6f	63	61	6c	56	61
80	72	69	61	62	6c	65	54	61	62	6c	65	01	00	04	74	68
90	69	73	01	00	20	4c	63	6f	6d	2f	6d	6f	62	69	6c	65
a0	66	69	73	68	2f	74	65	73	74	2f	48	65	6c	6c	6f	57
b0	6f	72	6c	64	3b	01	00	04	6d	61	69	6e	01	00	16	28
c0	5b	4c	6a	61	76	61	2f	6c	61	6e	67	2f	53	74	72	69
d0	6e	67	3b	29	56	09	00	11	00	13	07	00	12	01	00	10
e0	6a	61	76	61	2f	6c	61	6e	67	2f	53	79	73	74	65	6d
f0	0c	00	14	00	15	01	00	03	6f	75	74	01	00	15	4c	6a
100	61	76	61	2f	69	6f	2f	50	72	69	6e	74	53	74	72	65
110	61	6d	3b	08	00	17	01	00	27	48	65	6c	6c	6f	20	77
120	6f	72	6c	64	2c	20	77	65	6c	63	6f	6d	65	20	74	6f
130	20	4d	6f	62	69	6c	65	66	69	73	68	2e	63	6f	6d	2e
140	0a	00	19	00	1b	07	00	1a	01	00	13	6a	61	76	61	2f
150	69	6f	2f	50	72	69	6e	74	53	74	72	65	61	6d	0c	00
160	1c	00	1d	01	00	07	70	72	69	6e	74	6c	6e	01	00	15
170	28	4c	6a	61	76	61	2f	6c	61	6e	67	2f	53	74	72	69
180	6e	67	3b	29	56	01	00	04	61	72	67	73	01	00	13	5b
190	4c	6a	61	76	61	2f	6c	61	6e	67	2f	53	74	72	69	6e
1a0	67	3b	01	00	0a	53	6f	75	72	63	65	46	69	6c	65	01
1b0	00	0f	48	65	6c	6c	6f	57	6f	72	6c	64	2e	6a	61	76
1c0	61	00	21	00	01	00	03	00	00	00	00	00	02	00	01	00
1d0	05	00	06	00	01	00	07	00	00	00	2f	00	01	00	01	00
1e0	00	00	05	2a	b7	00	08	b1	00	00	00	02	00	0a	00	00
1f0	00	06	00	01	00	00	00	03	00	0b	00	00	00	0c	00	01
200	00	00	00	05	00	0c	00	0d	00	00	00	09	00	0e	00	0f
210	00	01	00	07	00	00	00	37	00	02	00	01	00	00	00	09
220	b2	00	10	12	16	b6	00	18	b1	00	00	00	02	00	0a	00
230	00	00	0a	00	02	00	00	00	05	00	08	00	06	00	0b	00
240	00	00	0c	00	01	00	00	00	09	00	1e	00	1f	00	00	00
250	01	00	20	00	00	00	02	00	21

	0	1	2	3	4	5	6	7	8	9	a	b	c	d	e	f
0	ca	fe	ba	be	00	00	00	32	00	22	07	00	02	01	00	1e
10	63	6f	6d	2f	6d	6f	62	69	6c	65	66	69	73	68	2f	74
20	65	73	74	2f	48	65	6c	6c	6f	57	6f	72	6c	64	07	00
30	04	01	00	10	6a	61	76	61	2f	6c	61	6e	67	2f	4f	62
40	6a	65	63	74	01	00	06	3c	69	6e	69	74	3e	01	00	03
50	28	29	56	01	00	04	43	6f	64	65	0a	00	03	00	09	0c
60	00	05	00	06	01	00	0f	4c	69	6e	65	4e	75	6d	62	65
70	72	54	61	62	6c	65	01	00	12	4c	6f	63	61	6c	56	61
80	72	69	61	62	6c	65	54	61	62	6c	65	01	00	04	74	68
90	69	73	01	00	20	4c	63	6f	6d	2f	6d	6f	62	69	6c	65
a0	66	69	73	68	2f	74	65	73	74	2f	48	65	6c	6c	6f	57
b0	6f	72	6c	64	3b	01	00	04	6d	61	69	6e	01	00	16	28
c0	5b	4c	6a	61	76	61	2f	6c	61	6e	67	2f	53	74	72	69
d0	6e	67	3b	29	56	09	00	11	00	13	07	00	12	01	00	10
e0	6a	61	76	61	2f	6c	61	6e	67	2f	53	79	73	74	65	6d
f0	0c	00	14	00	15	01	00	03	6f	75	74	01	00	15	4c	6a
100	61	76	61	2f	69	6f	2f	50	72	69	6e	74	53	74	72	65
110	61	6d	3b	08	00	17	01	00	27	48	65	6c	6c	6f	20	77
120	6f	72	6c	64	2c	20	77	65	6c	63	6f	6d	65	20	74	6f
130	20	4d	6f	62	69	6c	65	66	69	73	68	2e	63	6f	6d	2e
140	0a	00	19	00	1b	07	00	1a	01	00	13	6a	61	76	61	2f
150	69	6f	2f	50	72	69	6e	74	53	74	72	65	61	6d	0c	00
160	1c	00	1d	01	00	07	70	72	69	6e	74	6c	6e	01	00	15
170	28	4c	6a	61	76	61	2f	6c	61	6e	67	2f	53	74	72	69
180	6e	67	3b	29	56	01	00	04	61	72	67	73	01	00	13	5b
190	4c	6a	61	76	61	2f	6c	61	6e	67	2f	53	74	72	69	6e
1a0	67	3b	01	00	0a	53	6f	75	72	63	65	46	69	6c	65	01
1b0	00	0f	48	65	6c	6c	6f	57	6f	72	6c	64	2e	6a	61	76
1c0	61	00	21	00	01	00	03	00	00	00	00	00	02	00	01	00
1d0	05	00	06	00	01	00	07	00	00	00	2f	00	01	00	01	00
1e0	00	00	05	2a	b7	00	08	b1	00	00	00	02	00	0a	00	00
1f0	00	06	00	01	00	00	00	03	00	0b	00	00	00	0c	00	01
200	00	00	00	05	00	0c	00	0d	00	00	00	09	00	0e	00	0f
210	00	01	00	07	00	00	00	37	00	02	00	01	00	00	00	09
220	b2	00	10	12	16	b6	00	18	b1	00	00	00	02	00	0a	00
230	00	00	0a	00	02	00	00	00	05	00	08	00	06	00	0b	00
240	00	00	0c	00	01	00	00	00	09	00	1e	00	1f	00	00	00
250	01	00	20	00	00	00	02	00	21

	0	1	2	3	4	5	6	7	8	9	a	b	c	d	e	f
0	ca	fe	ba	be	00	00	00	32	00	22	07	00	02	01	00	1e
10	63	6f	6d	2f	6d	6f	62	69	6c	65	66	69	73	68	2f	74
20	65	73	74	2f	48	65	6c	6c	6f	57	6f	72	6c	64	07	00
30	04	01	00	10	6a	61	76	61	2f	6c	61	6e	67	2f	4f	62
40	6a	65	63	74	01	00	06	3c	69	6e	69	74	3e	01	00	03
50	28	29	56	01	00	04	43	6f	64	65	0a	00	03	00	09	0c
60	00	05	00	06	01	00	0f	4c	69	6e	65	4e	75	6d	62	65
70	72	54	61	62	6c	65	01	00	12	4c	6f	63	61	6c	56	61
80	72	69	61	62	6c	65	54	61	62	6c	65	01	00	04	74	68
90	69	73	01	00	20	4c	63	6f	6d	2f	6d	6f	62	69	6c	65
a0	66	69	73	68	2f	74	65	73	74	2f	48	65	6c	6c	6f	57
b0	6f	72	6c	64	3b	01	00	04	6d	61	69	6e	01	00	16	28
c0	5b	4c	6a	61	76	61	2f	6c	61	6e	67	2f	53	74	72	69
d0	6e	67	3b	29	56	09	00	11	00	13	07	00	12	01	00	10
e0	6a	61	76	61	2f	6c	61	6e	67	2f	53	79	73	74	65	6d
f0	0c	00	14	00	15	01	00	03	6f	75	74	01	00	15	4c	6a
100	61	76	61	2f	69	6f	2f	50	72	69	6e	74	53	74	72	65
110	61	6d	3b	08	00	17	01	00	27	48	65	6c	6c	6f	20	77
120	6f	72	6c	64	2c	20	77	65	6c	63	6f	6d	65	20	74	6f
130	20	4d	6f	62	69	6c	65	66	69	73	68	2e	63	6f	6d	2e
140	0a	00	19	00	1b	07	00	1a	01	00	13	6a	61	76	61	2f
150	69	6f	2f	50	72	69	6e	74	53	74	72	65	61	6d	0c	00
160	1c	00	1d	01	00	07	70	72	69	6e	74	6c	6e	01	00	15
170	28	4c	6a	61	76	61	2f	6c	61	6e	67	2f	53	74	72	69
180	6e	67	3b	29	56	01	00	04	61	72	67	73	01	00	13	5b
190	4c	6a	61	76	61	2f	6c	61	6e	67	2f	53	74	72	69	6e
1a0	67	3b	01	00	0a	53	6f	75	72	63	65	46	69	6c	65	01
1b0	00	0f	48	65	6c	6c	6f	57	6f	72	6c	64	2e	6a	61	76
1c0	61	00	21	00	01	00	03	00	00	00	00	00	02	00	01	00
1d0	05	00	06	00	01	00	07	00	00	00	2f	00	01	00	01	00
1e0	00	00	05	2a	b7	00	08	b1	00	00	00	02	00	0a	00	00
1f0	00	06	00	01	00	00	00	03	00	0b	00	00	00	0c	00	01
200	00	00	00	05	00	0c	00	0d	00	00	00	09	00	0e	00	0f
210	00	01	00	07	00	00	00	37	00	02	00	01	00	00	00	09
220	b2	00	10	12	16	b6	00	18	b1	00	00	00	02	00	0a	00
230	00	00	0a	00	02	00	00	00	05	00	08	00	06	00	0b	00
240	00	00	0c	00	01	00	00	00	09	00	1e	00	1f	00	00	00
250	01	00	20	00	00	00	02	00	21