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진격의안드로이드&Java

Difference between r1.5 and the current

@@ -1,10 +1,27 @@
[[Tableofcontents]]
== 강의록 ==
* [http://www.slideshare.net/novathinker/1-java-key Chapter 1]
* [http://www.slideshare.net/novathinker/2-runtime-data-areas Chapter 2]
* [http://www.slideshare.net/novathinker/1-java-key Java-Chapter 1]
* [http://www.slideshare.net/novathinker/2-runtime-data-areas Java-Chapter 2]
* [http://www.kandroid.org/board/data/board/conference/file_in_body/1/8th_kandroid_application_framework.pdf Android]

== 강의 내용 ==
=== ByteCode.java ===
==== cmd에서 Compile & Decompile 방법 ====
{{{
// Compile
// notepad++ 에서 UTF8(BOM 없음) 선택후 다음과 같이 cmd에서 컴파일
 
javac -encoding utf8 ByteCode.java
}}}
 
{{{
// Decompile
 
javap -c ByteCode.class
}}}
 
==== 기본 소스 ====
{{{#!vim java
public class ByteCode{
public ByteCode() {
System.out.println("hello");
@@ -18,3 +35,118 @@
}
}
}}}
 
{{{#!vim java
// Result of Decompile
 
Compiled from "ByteCode.java"
public class ByteCode {
public ByteCode();
Code:
0: aload_0
1: invokespecial #1 // Method java/lang/Object."<init>":()V
4: getstatic #2 // Field java/lang/System.out:Ljava/io/PrintStream;
7: ldc #3 // String hello
9: invokevirtual #4 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
12: return
 
public void methodOperandStack();
Code:
0: iconst_5
1: istore_1
2: iconst_1
3: istore_2
4: iload_1
5: iload_2
6: iadd
7: istore_3
8: return
}
}}}
 
==== 1차 수정 ====
{{{#!vim java
public class ByteCode{
public ByteCode() {
System.out.println("hello");
}
public void methodOperandStack(){
try{
int a, b, c;
a = 5;
b = 1;
c = a + b;
} catch(Exception e){
}
}
}
}}}
 
{{{#!vim java
// Result of Decompile
 
Compiled from "ByteCode.java"
public class ByteCode {
public ByteCode();
Code:
0: aload_0
1: invokespecial #1 // Method java/lang/Object."<init>":()V
4: getstatic #2 // Field java/lang/System.out:Ljava/io/PrintStream;
7: ldc #3 // String hello
9: invokevirtual #4 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
12: return
 
public void methodOperandStack();
Code:
0: iconst_5
1: istore_1
2: iconst_1
3: istore_2
4: iload_1
5: iload_2
6: iadd
7: istore_3
8: goto 12
11: astore_1
12: return
Exception table:
from to target type
0 8 11 Class java/lang/Exception
}
}}}
 
==== 2차 수정 ====
{{{#!vim java
public class ByteCode{
public ByteCode() {
System.out.println("hello");
}
private static final boolean optimize = false;
private final void methodOperandStack(){
if(optimize){
int a, b, c;
a = 5;
b = 1;
c = a + b;
}
}
}
}}}
 
{{{#!vim java
// Result of Decompile
 
Compiled from "ByteCode.java"
public class ByteCode {
public ByteCode();
Code:
0: aload_0
1: invokespecial #1 // Method java/lang/Object."<init>":()V
4: getstatic #2 // Field java/lang/System.out:Ljava/io/PrintStream;
7: ldc #3 // String hello
9: invokevirtual #4 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
12: return
}
}}}



1. 강의록

2. 강의 내용

2.1. ByteCode.java

2.1.1. cmd에서 Compile & Decompile 방법 

// Compile
// notepad++ 에서 UTF8(BOM 없음) 선택후 다음과 같이 cmd에서 컴파일

javac -encoding utf8 ByteCode.java


// Decompile

javap -c ByteCode.class

2.1.2. 기본 소스 

public class ByteCode{
        public ByteCode() {
                System.out.println("hello");
        }

        public void methodOperandStack(){
                int a, b, c;
                a = 5;
                b = 1;
                c = a + b;
        }
}


// Result of Decompile

Compiled from "ByteCode.java"
public class ByteCode {
  public ByteCode();
    Code:
       0: aload_0
       1: invokespecial #1                  // Method java/lang/Object."<init>":()V
       4: getstatic     #2                  // Field java/lang/System.out:Ljava/io/PrintStream;
       7: ldc           #3                  // String hello
       9: invokevirtual #4                  // Method java/io/PrintStream.println:(Ljava/lang/String;)V
      12: return

  public void methodOperandStack();
    Code:
       0: iconst_5
       1: istore_1
       2: iconst_1
       3: istore_2
       4: iload_1
       5: iload_2
       6: iadd
       7: istore_3
       8: return
}

2.1.3. 1차 수정 

public class ByteCode{
        public ByteCode() {
                System.out.println("hello");
        }

        public void methodOperandStack(){
                try{
                        int a, b, c;
                        a = 5;
                        b = 1;
                        c = a + b;
                } catch(Exception e){
                }
        }
}


// Result of Decompile

Compiled from "ByteCode.java"
public class ByteCode {
  public ByteCode();
    Code:
       0: aload_0
       1: invokespecial #1                  // Method java/lang/Object."<init>":()V
       4: getstatic     #2                  // Field java/lang/System.out:Ljava/io/PrintStream;
       7: ldc           #3                  // String hello
       9: invokevirtual #4                  // Method java/io/PrintStream.println:(Ljava/lang/String;)V
      12: return

  public void methodOperandStack();
    Code:
       0: iconst_5
       1: istore_1
       2: iconst_1
       3: istore_2
       4: iload_1
       5: iload_2
       6: iadd
       7: istore_3
       8: goto          12
      11: astore_1
      12: return
    Exception table:
       from    to  target type
           0     8    11   Class java/lang/Exception
}

2.1.4. 2차 수정 

public class ByteCode{
        public ByteCode() {
                System.out.println("hello");
        }

        private static final boolean optimize = false;
        private final void methodOperandStack(){
                if(optimize){
                        int a, b, c;
                        a = 5;
                        b = 1;
                        c = a + b;
                }
        }
}


// Result of Decompile

Compiled from "ByteCode.java"
public class ByteCode {
  public ByteCode();
    Code:
       0: aload_0
       1: invokespecial #1                  // Method java/lang/Object."<init>":()V
       4: getstatic     #2                  // Field java/lang/System.out:Ljava/io/PrintStream;
       7: ldc           #3                  // String hello
       9: invokevirtual #4                  // Method java/io/PrintStream.println:(Ljava/lang/String;)V
      12: return
}
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