public class Student{
	public String name;
	public int age;
	
	public int add(int a,int b){
		return a+b;
	}
}

kb-jaydeMacBook-Air:Desktop kb_jay$ javac Student.java
kb-jaydeMacBook-Air:Desktop kb_jay$ javap -verbose Student
Classfile /Users/kb_jay/Desktop/Student.class
  Last modified 2019-9-10; size 298 bytes
  MD5 checksum fec35654474a4425fb9a2abfbcc72a07
  Compiled from "Student.java"
public class Student
  minor version: 0      //副版本号
  major version: 52		//主版本号
  flags: ACC_PUBLIC, ACC_SUPER   //类访问标志
Constant pool:          //常量池，这里是类文件的资源池
   #1 = Methodref          #3.#16         // java/lang/Object."<init>":()V
   #2 = Class              #17            // Student
   #3 = Class              #18            // java/lang/Object
   #4 = Utf8               name
   #5 = Utf8               Ljava/lang/String;
   #6 = Utf8               age
   #7 = Utf8               I
   #8 = Utf8               <init>
   #9 = Utf8               ()V
  #10 = Utf8               Code
  #11 = Utf8               LineNumberTable
  #12 = Utf8               add
  #13 = Utf8               (II)I
  #14 = Utf8               SourceFile
  #15 = Utf8               Student.java
  #16 = NameAndType        #8:#9          // "<init>":()V
  #17 = Utf8               Student
  #18 = Utf8               java/lang/Object
{
	//字段表，这里的描述符，如果做过ndk，应该很熟悉了
  public java.lang.String name;
    descriptor: Ljava/lang/String;
    flags: ACC_PUBLIC

  public int age;
    descriptor: I
    flags: ACC_PUBLIC

	//方法表
  public Student();
  	//方法描述符，ndk开发常用
    descriptor: ()V
    flags: ACC_PUBLIC
    //code是属性表中的一个，
    Code:
    	//操作数栈，局部变量表，参数个数，这里是this
      stack=1, locals=1, args_size=1
      	//字节码指令
         0: aload_0
         1: invokespecial #1                  // Method java/lang/Object."<init>":()V
         4: return
      //LineNumberTable是属性表中的一个，抛出异常的时的异常代码的位置
      LineNumberTable:
        line 1: 0

  public int add(int, int);
    descriptor: (II)I
    flags: ACC_PUBLIC
    Code:
      stack=2, locals=3, args_size=3
         0: iload_1
         1: iload_2
         2: iadd
         3: ireturn
      LineNumberTable:
        line 6: 0
}
SourceFile: "Student.java"