Java 10 Garbage-Collector Interface
JDK 10 is type inference of local variables with initializers. This tutorial provides the details of LocalVariable Type-Inference with examples.
Java has now var style declarations. It allows you to declare a local variable without specifying its type.var won’t work without the initializer:
Nor would it work if initialized with null:
var n; // error: cannot use 'var' on variable without initializer
var emptyList = null; // error: variable initializer is 'null'
vardeclaration and initialization at same time
var, you must initialize the variable at same place. You cannot put declaration and initialization at different places. If you do not initialize the variable in place, then you will get compilation error –
Cannot use 'var' on variable without initializer.
var i; //Invalid Declaration - - Cannot use 'var' on variable without initializer var j = 10; //Valid Declaration System.out.println(i);
//Invalid Declaration - - Cannot use 'var' on variable without initializer
var j =
var is restricted to – local variables with initializers, indexes in the enhanced for-loop, and locals declared in a traditional for-loop; it would not be available for method formals, constructor formals, method return types, fields, catch formals, or any other kind of variable declaration.
Usage allowed as :
- Local variables with initializers
- Indexes in the enhanced for-loop
- Locals declared in a traditional for-loop