内部类被实例化才会被加载进内存测试

D:JavaProjectSpringProjectdemo_spring_Synchronized	argetclassesjulywilddemo11>javap -v -p Test06.class
Classfile /D:/JavaProject/SpringProject/demo_spring_Synchronized/target/classes/july/wild/demo11/Test06.class
  Last modified 2020年8月3日; size 380 bytes
  MD5 checksum 3d6bee6c0a5d3d2000866ed1bad13d03
  Compiled from "Test06.java"
public class july.wild.demo11.Test06
  minor version: 0
  major version: 55
  flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: #2                          // july/wild/demo11/Test06
  super_class: #3                         // java/lang/Object
  interfaces: 0, fields: 1, methods: 2, attributes: 1
Constant pool:
   #1 = Methodref          #3.#16         // java/lang/Object."<init>":()V
   #2 = Class              #17            // july/wild/demo11/Test06
   #3 = Class              #18            // java/lang/Object
   #4 = Utf8               dog
   #5 = Utf8               Ljuly/wild/demo11/Dog;
   #6 = Utf8               <init>
   #7 = Utf8               ()V
   #8 = Utf8               Code
   #9 = Utf8               LineNumberTable
  #10 = Utf8               LocalVariableTable
  #11 = Utf8               this
  #12 = Utf8               Ljuly/wild/demo11/Test06;
  #13 = Utf8               test
  #14 = Utf8               SourceFile
  #15 = Utf8               Test06.java
  #16 = NameAndType        #6:#7          // "<init>":()V
  #17 = Utf8               july/wild/demo11/Test06
  #18 = Utf8               java/lang/Object
{
  july.wild.demo11.Dog dog;
    descriptor: Ljuly/wild/demo11/Dog;
    flags: (0x0000)

  public july.wild.demo11.Test06();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
         0: aload_0
         1: invokespecial #1                  // Method java/lang/Object."<init>":()V
         4: return
      LineNumberTable:
        line 9: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
            0       5     0  this   Ljuly/wild/demo11/Test06;

  void test();
    descriptor: ()V
    flags: (0x0000)
    Code:
      stack=0, locals=1, args_size=1
         0: return
      LineNumberTable:
        line 14: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
            0       1     0  this   Ljuly/wild/demo11/Test06;
}
SourceFile: "Test06.java"

D:JavaProjectSpringProjectdemo_spring_Synchronized	argetclassesjulywilddemo11>javap -v -p Test06.class
Classfile /D:/JavaProject/SpringProject/demo_spring_Synchronized/target/classes/july/wild/demo11/Test06.class
  Last modified 2020年8月3日; size 380 bytes
  MD5 checksum 3d6bee6c0a5d3d2000866ed1bad13d03
  Compiled from "Test06.java"
public class july.wild.demo11.Test06
  minor version: 0
  major version: 55
  flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: #2                          // july/wild/demo11/Test06
  super_class: #3                         // java/lang/Object
  interfaces: 0, fields: 1, methods: 2, attributes: 1
Constant pool:
   #1 = Methodref          #3.#16         // java/lang/Object."<init>":()V
   #2 = Class              #17            // july/wild/demo11/Test06
   #3 = Class              #18            // java/lang/Object
   #4 = Utf8               dog
   #5 = Utf8               Ljuly/wild/demo11/Dog;
   #6 = Utf8               <init>
   #7 = Utf8               ()V
   #8 = Utf8               Code
   #9 = Utf8               LineNumberTable
  #10 = Utf8               LocalVariableTable
  #11 = Utf8               this
  #12 = Utf8               Ljuly/wild/demo11/Test06;
  #13 = Utf8               test
  #14 = Utf8               SourceFile
  #15 = Utf8               Test06.java
  #16 = NameAndType        #6:#7          // "<init>":()V
  #17 = Utf8               july/wild/demo11/Test06
  #18 = Utf8               java/lang/Object
{
  july.wild.demo11.Dog dog;
    descriptor: Ljuly/wild/demo11/Dog;
    flags: (0x0000)

  public july.wild.demo11.Test06();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
         0: aload_0
         1: invokespecial #1                  // Method java/lang/Object."<init>":()V
         4: return
      LineNumberTable:
        line 9: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
            0       5     0  this   Ljuly/wild/demo11/Test06;

  void test();
    descriptor: ()V
    flags: (0x0000)
    Code:
      stack=0, locals=1, args_size=1
         0: return
      LineNumberTable:
        line 14: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
            0       1     0  this   Ljuly/wild/demo11/Test06;
}
SourceFile: "Test06.java"

上面是两段代码的反编译之后的结果：

 一个实例化了Dog 一个没有，从反编译结果看出：内部类的特点Dog()：Dog被实例化就会加载Dog类，没有实例化则不会加载Dog类