Yes, Java allows to save our java file by .java only, we need to compile it by javac .java and run by java classname Let's take a simple example:

compile it by javac .java

run it by java A

No.

It is empty, but not null.

The program compiles and runs correctly because the order of specifiers doesn't matter in Java.

The local variables are not initialized to any default value, neither primitives nor object references.

In Java, access specifiers are the keywords which are used to define the access scope of the method, class, or a variable. In Java, there are four access specifiers given below.

• Public The classes, methods, or variables which are defined as public, can be accessed by any class or method.
• Protected Protected can be accessed by the class of the same package, or by the sub-class of this class, or within the same class.
• Default Default are accessible within the package only. By default, all the classes, methods, and variables are of default scope.
• Private The private class, methods, or variables defined as private can be accessed within the class only.

The methods or variables defined as static are shared among all the objects of the class. The static is the part of the class and not of the object. The static variables are stored in the class area, and we do not need to create the object to access such variables. Therefore, static is used in the case, where we need to define variables or methods which are common to all the objects of the class.

For example, In the class simulating the collection of the students in a college, the name of the college is the common attribute to all the students. Therefore, the college name will be defined as static.

There are various advantages of defining packages in Java.

• Packages avoid the name clashes.
• The Package provides easier access control.
• We can also have the hidden classes that are not visible outside and used by the package.
• It is easier to locate the related classes.

The output of the above code will be

 30FresherGate FresherGate1020 

Explanation

In the first case, 10 and 20 are treated as numbers and added to be 30. Now, their sum 30 is treated as the string and concatenated with the stringFresherGate. Therefore, the output will be 30FresherGate.

In the second case, the string FresherGate is concatenated with 10 to be the string FresherGate10 which will then be concatenated with 20 to be FresherGate1020.