transient: An instance variable is marked transient to indicate the JVM to skip the particular variable when serializing the object containing it.  This modifier is included in the statement that creates the variable, preceding the class or data type of the variable.Examplepublic transient int limit = 55;   // will not persist public int b;   // will persistvolatile: The volatile modifier is used to let the JVM know that a thread accessing the variable must always merge its own private copy of the variable with the master copy in the memory.Accessing a volatile variable synchronizes all the cached copied ... Read More

The volatile modifier is used to let the JVM understand that a thread accessing the variable should always merge its own personal copy of the variable with the original in the memory.Accessing a volatile variable synchronizes all the cached copy of the variables in the main memory. Volatile can only be applied to instance variables, which are of type object or private. A volatile object reference can be null.Examplepublic class MyRunnable implements Runnable {    private volatile boolean active;    public void run() {       active = true;       while (active) {           }    }    public void stop() {       active = false;      } }

An instance variable is marked transient to point the JVM to skip the actual variable once serializing the thing containing it. This modifier is included in the statement that creates the variable, preceding the class or data type of the variable. Example public class Employee implements java.io.Serializable { public String name; public String address; public transient int SSN; public int number; public void mailCheck() { System.out.println("Mailing a check to " + name + " ... Read More

Yes, a local variable can be public, private, protected or default.

The final modifier can be associated with methods, classes and variables. Once declared final − A final class cannot be instantiated. A final method cannot be overridden. A final variable cannot be reassigned. Example Live Demo class TestExample { final int value = 10; public static final int BOXWIDTH = 6; static final String TITLE = "Manager"; public final void changeName() { System.out.println("This is a final method"); } } final class ... Read More

An abstract keyword is used to declare methods abstract methods and abstract classes. Once a method is declared abstract we should not specify body for those. Example public abstract class Sample{ public abstract demo(){ } } Error Sample.java:2: error: invalid method declaration; return type required public abstract demo(){ ^ 1 error And once a class is declared abstract it cannot be instantiated. Example public abstract class Sample{ public abstract void demo(); public static void main(String args[]){ new Sample(); } } Error C:\Sample>javac Sample.java Sample.java:4: error: Sample is abstract; cannot be instantiated new Sample(); ^ 1 error

The synchronized keyword used to indicate that a method can be accessed by only one thread at a time. The synchronized modifier can be applied with any of the four access level modifiers. Example Live Demo public class TestThread { public static Object Lock1 = new Object(); public static Object Lock2 = new Object(); public static void main(String args[]) { ThreadDemo1 T1 = new ThreadDemo1(); ThreadDemo2 T2 = new ThreadDemo2(); ... Read More

We can declare an array as a local variable or method parameter but, an array cannot be static. Example public class Test{ public void sample(){ static int[] myArray = {20, 30}; System.out.println(); } public static void main(String args[]){ Test t = new Test(); t.sample(); } } Error C:\Sample>javac Test.java Test.java:3: error: illegal start of expression static int[] myArray = {20, 30}; ^ 1 error

The abstract keyword is used to declare methods abstract methods and abstract classes. Once a method is declared abstract we should not specify body for those. And once a class is declared abstract it cannot be instantiated. Example Live Demo abstract class Employee { private String name; private String address; private int number; public Employee(String name, String address, int number) { System.out.println("Constructing an Employee"); this.name = name; ... Read More

You can pass final variables as the parameters to methods in Java. A final variable can be explicitly initialized only once. A reference variable declared final can never be reassigned to refer to a different object. However, the data within the object can be changed. So, the state of the object can be changed but not the reference. With variables, the final modifier often is used with static to make the constant a class variable. Example Live Demo public class Test{ public void sample(final int data){ System.out.println(data); ... Read More