In JAVA enumeration (why the output is the name of the enumeration values rather than address value)-CodePudding

Public class Test {
Enum Color {
RED, GREEN, BLUE;
}
}

//execution output
Public static void main (String [] args) {
Color c1=Color. RED;
System. The out. Println (c1);
}
//output is the result of the RED
//why output is RED, the address values should not be RED?

CodePudding user response:

1. All the enumeration is inherited from an Enum

2. Enum override the toString method

 public String toString () {
return name; 
}

CodePudding user response:

Because enumerated types the resulting class files after the decompiled code is
Public final class Color extends Enum
{
Public static Color [] values ()
{
Return (Color []) $VALUES. The clone ();
}

Public static Color the valueOf (String name)
{
Return (Color) Enum. The valueOf (Color, name);
}

Private Color (String s, int I)
{
Super (s, I);
}

Public static final Color RED;
Public static final Color GREEN;
Public static final Color BLUE.
Private static final Color $VALUES [];

The static
{
RED=new Color (" RED ", 0);
GREEN=new Color (" GREEN ", 1);
BLUE=new Color (" BLUE ", 2);
$VALUES=(new Color [] {
RED, GREEN, BLUE
});
}
}
The default toString method and enumeration class is such a
Public abstract class Enum
Implements Comparable , the Serializable {
//omit other code
Public String toString () {
return name;
}
}
And the name is private constructor
Private Color (String s, int I)
{
Super (s, I);
} the s
So, summarized as follows: each enumeration class finally after decompiling is inherited an enum, at the same time more private constructor
Private Color (String s, int I)
{
Super (s, I);
} and attribute name, and ultimately through the console output is this name, which is defined in the enumeration class each enumeration value

CodePudding user response:

reference 1st floor SJLZCJ response:

1. All the enumeration is inherited from an Enum

2. Enum override the toString method
 public String toString () {
return name; 
} 

The c1 and didn't call the toString () method!!!!!!

CodePudding user response:

2 floor have a reference to raw response:

because enumerated types the resulting class files after the decompiled code is
Public final class Color extends Enum
{
Public static Color [] values ()
{
Return (Color []) $VALUES. The clone ();
}

Public static Color the valueOf (String name)
{
Return (Color) Enum. The valueOf (Color, name);
}

Private Color (String s, int I)
{
Super (s, I);
}

Public static final Color RED;
Public static final Color GREEN;
Public static final Color BLUE.
Private static final Color $VALUES [];

The static
{
RED=new Color (" RED ", 0);
GREEN=new Color (" GREEN ", 1);
BLUE=new Color (" BLUE ", 2);
$VALUES=(new Color [] {
RED, GREEN, BLUE
});
}
}
The default toString method and enumeration class is such a
Public abstract class Enum
Implements Comparable , the Serializable {
//omit other code
Public String toString () {
return name;
}
}
And the name is private constructor
Private Color (String s, int I)
{
Super (s, I);
} the s
So, summarized as follows: each enumeration class finally after decompiling is inherited an enum, at the same time more private constructor
Private Color (String s, int I)
{
Super (s, I);
} and attribute name, and ultimately through the console output is this name, which is defined in the enumeration class each enumeration value

Thanks brother comments, but now I feel don't understand, I understand such as cough up again and see it

CodePudding user response:

reference Ao sink reply: 3/f

Quote: refer to 1st floor SJLZCJ response:
1. All the enumeration is inherited from an Enum

2. Enum override the toString method
public String toString () {
return name;
}

The c1 and didn't call the toString () method!!!!!!

Go to the next System. Out. Println (Object x) source code, inside the call Object. The toString () method of

 
//this is System. Out.println (Object x) method 
Public void println (Object) x {
//here will be posted on the String. The valueOf (x) method source code 
String s=String. The valueOf (x); 
Synchronized (this) {
Print (s); 
NewLine (); 
} 
} 

//this is a String. The valueOf (Object obj) method, called the obj toString () method 
Public static String the valueOf (Object obj) {
Return (obj==null)? "Null" : obj. ToString (); 
}