If I am not wrong, switchs are slower than else/if, so that is something to know about depending on your usage.

It depends. If you have only one alternative like x==4 and only two actions, I would go with an if-statement. If you have for example if(x==2||x==27||x==31){}else if(x==4||x==29||x==33){}else{} I would go with a switch statement. In this cases a switch-statement is more readable:

switch(x){   case 2:   case 27:   case 31:           foo();           break;   case 4:   case 29:   case 33:           bar();           break;   default:           throw new IllegalArgumentException("Invalid value for x: "+x); } 

From a performance POV I would say, if is faster, if there are only some cases (2-4), after that I would a switch-statement

Long story short: use whichever you like to use;

If you’re interested into internals, then keep reading. We don’t have to guess the answer on your question. I’ve written a simple example program and let’s see it in the actual implementation. First I’ll examine if-else, and then I’ll examine switch.

If-else

public class IfElse {      public static void main(String[] args) {          int x = Integer.valueOf(args[0]);          if (x==1) {             System.out.println("x is 1");         } else {             System.out.println("x is not 1");         }     } } 

Now, after we save this in the simple text editor and compile it with javac IfElse.java, Java compiler will generate a IfElse.class file which has the following bytecode:

javap -c IfElse.class Compiled from "IfElse.java" public class IfElse {   public IfElse();     Code:        0: aload_0        1: invokespecial #1                  // Method java/lang/Object."<init>":()V        4: return    public static void main(java.lang.String[]);     Code:        0: aload_0        1: iconst_0        2: aaload        3: invokestatic  #2                  // Method java/lang/Integer.valueOf:(Ljava/lang/String;)Ljava/lang/Integer;        6: invokevirtual #3                  // Method java/lang/Integer.intValue:()I        9: istore_1       10: iload_1       11: iconst_1       12: if_icmpne     26       15: getstatic     #4                  // Field java/lang/System.out:Ljava/io/PrintStream;       18: ldc           #5                  // String x is 1       20: invokevirtual #6                  // Method java/io/PrintStream.println:(Ljava/lang/String;)V       23: goto          34       26: getstatic     #4                  // Field java/lang/System.out:Ljava/io/PrintStream;       29: ldc           #7                  // String x is not 1       31: invokevirtual #6                  // Method java/io/PrintStream.println:(Ljava/lang/String;)V       34: return } 

Switch

public class Switch {      public static void main(String[] args) {              int x = Integer.valueOf(args[0]);          switch(x) {             case 1:                 System.out.println("x is 1");                 break;             default:                 System.out.println("x is not 1");         }     } } 

in the same way, we compile it with javac Switch.java and see the bytecode afterwards:

Compiled from "Switch.java" public class Switch {   public Switch();     Code:        0: aload_0        1: invokespecial #1                  // Method java/lang/Object."<init>":()V        4: return    public static void main(java.lang.String[]);     Code:        0: aload_0        1: iconst_0        2: aaload        3: invokestatic  #2                  // Method java/lang/Integer.valueOf:(Ljava/lang/String;)Ljava/lang/Integer;        6: invokevirtual #3                  // Method java/lang/Integer.intValue:()I        9: istore_1       10: iload_1       11: lookupswitch  { // 1                      1: 28                default: 39           }       28: getstatic     #4                  // Field java/lang/System.out:Ljava/io/PrintStream;       31: ldc           #5                  // String x is 1       33: invokevirtual #6                  // Method java/io/PrintStream.println:(Ljava/lang/String;)V       36: goto          47       39: getstatic     #4                  // Field java/lang/System.out:Ljava/io/PrintStream;       42: ldc           #7                  // String x is not 1       44: invokevirtual #6                  // Method java/io/PrintStream.println:(Ljava/lang/String;)V       47: return } 

Conclusion:

switch operator has:

1. a bit more Java code to be written;

2. a bit more bytecode after compilation. Namely this:

    11: lookupswitch  { // 1          1: 28          default: 39      }