CODEWITHSUNDEEP
java
Mukul Sharma
Mukul Sharma

Reputation: 39

Are outer enums classes static implicitly?

while reading about the enums. I came through the post, Static enum vs. Non-static enum where outer enums are answered as static implicitly.

I created a enum and when I checked the byte code, enums are made as final but not static.

final class practice.Enums extends java.lang.Enum<practice.Enums> {
  public static final practice.Enums FRIEND;

  static {};
    Code:
       0: new           #1                  // class practice/Enums
       3: dup
       4: ldc           #12                 // String FRIEND
       6: iconst_0
       7: invokespecial #13                 // Method "<init>":(Ljava/lang/String;I)V
      10: putstatic     #17                 // Field FRIEND:Lpractice/Enums;
      13: iconst_1
      14: anewarray     #1                  // class practice/Enums
      17: dup
      18: iconst_0
      19: getstatic     #17                 // Field FRIEND:Lpractice/Enums;
      22: aastore
      23: putstatic     #19                 // Field ENUM$VALUES:[Lpractice/Enums;
      26: return

  public static practice.Enums[] values();
    Code:
       0: getstatic     #19                 // Field ENUM$VALUES:[Lpractice/Enums;
       3: dup
       4: astore_0
       5: iconst_0
       6: aload_0
       7: arraylength
       8: dup
       9: istore_1
      10: anewarray     #1                  // class practice/Enums
      13: dup
      14: astore_2
      15: iconst_0
      16: iload_1
      17: invokestatic  #27                 // Method java/lang/System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
      20: aload_2
      21: areturn

  public static practice.Enums valueOf(java.lang.String);
    Code:
       0: ldc           #1                  // class practice/Enums
       2: aload_0
       3: invokestatic  #35                 // Method java/lang/Enum.valueOf:(Ljava/lang/Class;Ljava/lang/String;)Ljava/lang/Enum;
       6: checkcast     #1                  // class practice/Enums
       9: areturn
}

please help me understand the if outer enums are static why they are not declared in byte code?

Upvotes: 1

Views: 44

Answers (1)

Austin Schaefer
Austin Schaefer

Reputation: 696

The class itself is not static, but all Enum members are inherently declared as public, static, and final.

For info about how to simulate a static class, see this.

Upvotes: 1

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