JAva,dexファイルコンパイル逆コンパイル

class Test
{
  int func(int a,int b){
    return (a+b)*(a-b);
  }

  public static void main(String[]args){
    Test test=new Test();
    System.out.println(test.func(3,4));
  }
}

Test.javaとして保存
.classファイルjavac Test.javaの生成
Javaバイトコードjavap Test.class>Testの生成
dxはbuild-toolsにあります
dexファイルdx--dex--output=Test.dex Test.classを生成
dexdumpはbuild-toolsにあります
dexdump -d Test.dex > Test_dex
JAVAバイトコード

Compiled from "Test.java"
class Test {
  Test();
    Code:
       0: aload_0       
       1: invokespecial #1                  // Method java/lang/Object."<init>":()V
       4: return        

  int func(int, int);
    Code:
       0: iload_1       
       1: iload_2       
       2: iadd          
       3: iload_1       
       4: iload_2       
       5: isub          
       6: imul          
       7: ireturn       

  public static void main(java.lang.String[]);
    Code:
       0: new           #2                  // class Test
       3: dup           
       4: invokespecial #3                  // Method "<init>":()V
       7: astore_1      
       8: getstatic     #4                  // Field java/lang/System.out:Ljava/io/PrintStream;
      11: aload_1       
      12: iconst_3      
      13: iconst_4      
      14: invokevirtual #5                  // Method func:(II)I
      17: invokevirtual #6                  // Method java/io/PrintStream.println:(I)V
      20: return        
}

dex

Processing 'Test.dex'...
Opened 'Test.dex', DEX version '035'
Class #0            -
  Class descriptor  : 'LTest;'
  Access flags      : 0x0000 ()
  Superclass        : 'Ljava/lang/Object;'
  Interfaces        -
  Static fields     -
  Instance fields   -
  Direct methods    -
    #0              : (in LTest;)
      name          : '<init>'
      type          : '()V'
      access        : 0x10000 (CONSTRUCTOR)
      code          -
      registers     : 1
      ins           : 1
      outs          : 1
      insns size    : 4 16-bit code units
00014c:                                        |[00014c] Test.<init>:()V
00015c: 7010 0400 0000                         |0000: invoke-direct {v0}, Ljava/lang/Object;.<init>:()V // method@0004
000162: 0e00                                   |0003: return-void
      catches       : (none)
      positions     : 
        0x0000 line=1
      locals        : 
        0x0000 - 0x0004 reg=0 this LTest; 

    #1              : (in LTest;)
      name          : 'main'
      type          : '([Ljava/lang/String;)V'
      access        : 0x0009 (PUBLIC STATIC)
      code          -
      registers     : 5
      ins           : 1
      outs          : 3
      insns size    : 17 16-bit code units
000164:                                        |[000164] Test.main:([Ljava/lang/String;)V
000174: 2200 0100                              |0000: new-instance v0, LTest; // type@0001
000178: 7010 0000 0000                         |0002: invoke-direct {v0}, LTest;.<init>:()V // method@0000
00017e: 6201 0000                              |0005: sget-object v1, Ljava/lang/System;.out:Ljava/io/PrintStream; // field@0000
000182: 1232                                   |0007: const/4 v2, #int 3 // #3
000184: 1243                                   |0008: const/4 v3, #int 4 // #4
000186: 6e30 0100 2003                         |0009: invoke-virtual {v0, v2, v3}, LTest;.func:(II)I // method@0001
00018c: 0a00                                   |000c: move-result v0
00018e: 6e20 0300 0100                         |000d: invoke-virtual {v1, v0}, Ljava/io/PrintStream;.println:(I)V // method@0003
000194: 0e00                                   |0010: return-void
      catches       : (none)
      positions     : 
        0x0000 line=8
        0x0005 line=9
        0x0010 line=10
      locals        : 

  Virtual methods   -
    #0              : (in LTest;)
      name          : 'func'
      type          : '(II)I'
      access        : 0x0000 ()
      code          -
      registers     : 5
      ins           : 3
      outs          : 0
      insns size    : 6 16-bit code units
000198:                                        |[000198] Test.func:(II)I
0001a8: 9000 0304                              |0000: add-int v0, v3, v4
0001ac: 9101 0304                              |0002: sub-int v1, v3, v4
0001b0: b210                                   |0004: mul-int/2addr v0, v1
0001b2: 0f00                                   |0005: return v0
      catches       : (none)
      positions     : 
        0x0000 line=4
      locals        : 
        0x0000 - 0x0006 reg=2 this LTest; 

  source_file_idx   : 7 (Test.java)