How the switch works

No. In Java, switch only works with constant values in case s. Other dynamic languages like Javascript can use variables in case s, but Java does not.

One of the reasons is how switch is compiled - it becomes a fixed table in the bytecode containing a mapping (from-to) of integer values to instructions addresses within methods. Since this table is fixed and constant in bytecodes, there is no way to depend on variable values that are only available at runtime.

For switch with enum s, the compiler transforms it into a switch into ordinal() of enum . In the case of switch with String s, the compiler transforms it into a switch with hashCode() s of String s (and uses a sequence of if s when hashes collide). However, switch will always be done through a fixed table determined at compilation time by mapping a number to a method instruction address.

Therefore, the most obvious alternative would be to use if . However, other alternatives are possible. For example:

• Transform the call to switch into a call to a polymorphic method of some object and transform each case into an implementation of this polymorphic method.

• If the goal of switch is within every case set a different value of the same variable, you can put all those values in an array, List or Map if switch is given by an access to an element of that array, List or Map .

• It is possible to use an array, List or Map of lambdas, implement in each lambda a functionality that would refer to case . As a result, switch would be replaced by access to an element of this array, List or Map and execution of the lambda obtained.

switch case is recommended when you have defined states and just want to check if a given variable "home" with some values. If you need to do any manipulation, you can do this before entering switch case or else opting for if else to make more complex config operations.

The case itself is already a comparison. You can not compare an expression with switch case . Ex:

The code below compiles:

switch(variavel) {
    case 1:
        System.out.println("Número 1");
        break;
}

The code below does not compiles:

switch(variavel) {
    case (variavel > 1):
        System.out.println("Número 1");
        break;
}

To make comparisons as the second case you should use if .