Gen's handling of arrays array

For example, the following:

public void T () {string[][] a = new string[][] {                  {"x", "Y"}              }; String[] B = new STRING[10]; String[] C = new string[] {"x", "Y"}; String[] D = {"X", "Y"};}

Where a is the same as the class content generated by the following statement:

string[][] A2 =  {{"x", "Y"}};

When initializing an array at creation time, the size of the array cannot be specified and an error is given below:

String[] C = new String[2] {"x", "Y"}; string[][] A1 = new string[2][] {{"x", "Y"}};

Eclipse Compiler Error: cannot define dimension expressions when a array initializer is provided

The resulting class content is as follows:

public void t (); Flags:acc_public code:stack=7, locals=5, args_size=1//Create the length of the first array 0:iconst_1//Create one-dimensional array, because there is only one element in the initialization module     , {"X", "Y"} 1:anewarray #2//Class "[Ljava/lang/string;"] 4:dup 5:iconst_0//Represents the No. 0 index of a two-dimensional array to be placed in a one-dimensional array value 6:iconst_2//Because the length of the one-dimensional array {"x", "Y"} is 2, so load the constant 2 7:ane Warray #3//class java/lang/string 10:dup 11:iconst_0//Location of the one-dimensional array index 0 storage x 12:LDC #4//S Tring x 14:aastore 15:dup 16:iconst_1//Store y 17:ldc #5//String y 19:aasto position in one-dimensional array index 1     Re 20:aastore 21:astore_1//Create a second array 22:bipush 24:anewarray #3//Class java/lang/string 27:astore_2//Create a third array 28:iconst_2 29:anewarray #3//class java/lang/string 32:dup 33:ic     ONST_0 34:LDC #4//String x 36:aastore 37:dup 38:iconst_1 39:ldc #5//String y 41:aastore 42:astore_3//Create a fourth array 43:iconSt_2 44:anewarray #3//class java/lang/string 47:dup 48:iconst_0 49:ldc #4//String X 51:aastore 52:dup 53:iconst_1 54:ldc #5//String y 56:aastore 57:astore 4 59: Return

Let's start with a detailed analysis of the first array creation process:

0:iconst_1  1:anewarray     #2                  //Class "[Ljava/lang/string;] 4:dup 5:iconst_0  6:iconst_2 7:anewarray     #3                  //class JAVA/LANG/STRING10:DUP11:ICONST_012:LDC           #4 
    //string X14:AASTORE15:DUP16:ICONST_117:LDC           #5                  //String y19:aastore20:aastore21:astore_1

The first array has the following tree structure:

The specific implementation process is as follows:

0:iconst_1
Call the Load method of Immediateitem (1) to load the constants into the Operation Stack

1:anewarray #2//Class "[Ljava/lang/string;"]
The one-dimensional array type is deposited into the constant pool and pressed into the stack directly into the array type string[]

4:dup
Generates a Stackitem (Object) and calls its duplicate () method

5:iconst_0
Call the Load method of Immediateitem (0) to load the constants into the Operation Stack

6:iconst_2
Call the Load method of Immediateitem (2) to load the constants into the Operation Stack

7:anewarray #3//Class java/lang/string
The string type is deposited into the constant pool and pressed into the stack directly into the type string

10:dup
Generates a Stackitem (Object) and calls its duplicate () method

11:iconst_0
Call the Load method of Immediateitem (0) to load the constants into the Operation Stack

12:LDC #4//String X
Call the Load method of Immediateitem ("X") to load the constant into the Operation Stack
14:aastore
Create and Invoke Indexeditem (object) and call its store () method

15:dup
16:iconst_1
17:LDC #5//String y
19:aastore

20:aastore
Returns Stackitem (object) for the following execution code
21:astore_1
Create and Invoke Indexeditem (object) and call its store () method

　　

　　

　

Gen's handling of arrays array