详解java中jvm虚拟机栈的作用

package com.lind.basic;

public class Demo1 {
 static int hello() {
 int a = 1;
 int b = 2;
 int c = a + b;
 return c;
 }

 public static void main(String[] args) {
 System.out.println(hello());
 }
}

Compiled from "Demo1.java"
public class com.lind.basic.Demo1 {
 public com.lind.basic.Demo1();
 Code:
  0: aload_0
  1: invokespecial #1     // Method java/lang/Object."<init>":()V
  4: return

 static int hello();
 Code:
  0: iconst_1 // 把第一个整型变量推到操作数栈
  1: istore_0 // 让它出栈，并存储到局部变量表
  2: iconst_2
  3: istore_1
  4: iload_0 // 加载第一个数据入操作数栈
  5: iload_1 // 加载第二个数据入操作数栈
  6: iadd // 将两个数相加，结束入操作数栈
  7: istore_2 // 将结果出栈，存到局部变量表
  8: iload_2 // 加载它入操作数栈
  9: ireturn // 返回

 public static void main(java.lang.String[]);
 Code:
  0: getstatic  #2     // Field java/lang/System.out:Ljava/io/PrintStream;
  3: invokestatic #3     // Method hello:()I
  6: invokevirtual #4     // Method java/io/PrintStream.println:(I)V
  9: return
}