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Mar 10, 2010 · 1. this is a reference to the current object. It is used in the constructor to distinguish between the local and the current class variable which have the same name. e.g.: public class circle {. int x; circle(int x){. this.x =x; //class variable =local variable. }
May 3, 2010 · 497. Assertions (by way of the assert keyword) were added in Java 1.4. They are used to verify the correctness of an invariant in the code. They should never be triggered in production code, and are indicative of a bug or misuse of a code path.
Jul 5, 2018 · 3. There are two different uses of volatile keyword. Prevents JVM from reading values from register (assume as cache), and forces its value to be read from memory. Reduces the risk of memory in-consistency errors. Prevents JVM from reading values in register, and forces its value to be read from memory.
7. The keyword static is used to denote a field or a method as belonging to the class itself and not to any particular instance. Using your code, if the object Clock is static, all of the instances of the Hello class will share this Clock data member (field) in common.
Mar 12, 2010 · I always try to use this keyword on local class objects. I use it to visually remind me if an object is static object or class object. It helps me and the compiler differentiate between method args and local class object. public void setValue(int value){ this.value = value; }
Jul 23, 2015 · Something that was overlooked in the other answers was its role in annotations. As far back as Java 1.5, the default keyword came about as a means to provide a default value for an annotation field. @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.TYPE) public @interface Processor {.
Jul 24, 2020 · The var is NOT a Java keyword. It's a reserved type name. It seems not a big difference but in fact, it IS: var var = 0; Here var is a variable name too, so the var can be used as a type name, but there is no restriction like for regular keyword (i.e. we can have a variable named var too). The actual type of the variable IS decided by the Java ...
May 11, 2015 · this.method1(); //but in a Foo2 instance, you must use this to do the same. public void method1() {} public Foo2(int val) {. this(val); //this will refer to the other Foo2 constructor. public Foo2(int val, int another) {. super(val, another); super.method1(); //this will refer to Foo.method1() @Override.
Sep 22, 2010 · The super keyword in Java is a reference variable that is used to refer to the immediate parent class object. Usage of Java super Keyword. super can be used to refer to the immediate parent class instance variable. super can be used to invoke the immediate parent class method. super () can be used to invoke immediate parent class constructor.
The new keyword does exactly what it says on the tin, it creates a brand new object, irrespective of whether one already exists. It creates a new object and stuffs the reference to that object inside the variable it has been given, overwriting any previous value (object) the variable held.
