- A process is an execution of a program, while a Thread is a single execution sequence within a process.

- A process can contain multiple threads. A Thread is sometimes called a lightweight process.

There are three ways that can be used in order for a Thread to be created:

A class may extend the Thread class.

A class may implement the Runnable interface.

An application can use the Executor framework, in order to create a thread pool.

The Runnable interface is preferred, as it does not require an object to inherit the Thread class. In case your application design requires multiple inheritance, only interfaces can help you. Also, the thread pool is very efficient and can be implemented and used very easily.

When an object is passed by value, this means that a copy of the object is passed. Thus, even if changes are made to that object, it doesn’t affect the original value. 

When an object is passed by reference, this means that the actual object is not passed, rather a reference of the object is passed. Thus, any changes made by the external method, are also reflected in all places.

1.Main difference is methods of a Java interface are implicitly abstract and cannot have implementations. A Java abstract class can have instance methods that implements a default behavior.

2.Variables declared in a Java interface is by default final. An abstract class may contain non-final variables.

3.Members of a Java interface are public by default. A Java abstract class can have the usual flavors of class members like private, protected, etc..

4.Java interface should be implemented using keyword “implements”; A Java abstract class should be extended using keyword “extends”.

5.An interface can extend another Java interface only, an abstract class can extend another Java class and implement multiple Java interfaces.

6.A Java class can implement multiple interfaces but it can extend only one abstract class.

7.Interface is absolutely abstract and cannot be instantiated; A Java abstract class also cannot be instantiated, but can be invoked if a main() exists.

8.In comparison with java abstract classes, java interfaces are slow as it requires extra indirection.

Autoboxing is the automatic conversion that the Java compiler makes between the primitive types and their corresponding object wrapper classes. For example, converting an int to an Integer, a double to a Double, and so on. If the conversion goes the other way, this is called unboxing. 

A static variable in Java belongs to its class and its value remains the same for all its instances. A static variable is initialized when the class is loaded by the JVM. If your code tries to access a non-static variable, without any instance, the compiler will complain, because those variables are not created yet and they are not associated with any instance.

Focus on your most recent accomplishments, those in your current position or the job you had just prior to this one. But make sure they are relevant to the position for which you're interviewing.

This is a good question to highlight your achievements. Don't be smug or arrogant about the success of a project, especially if it was a team effort. You need to give credit to the team, too. You could say what you contributed to the total project and also give credit to others that helped in your success. Don't be overly modest, either.Here are some pointers:

1. Pick something that was clearly a success and highlight your skills.

2. Pick something recent. If you pick something twenty years ago, they are going to wonder what you have done lately.

3. Pick something important. You may have succeeded in many projects that are not that significant. 

4. Pick something easy to explain. If complicated, give the short version.

5. Be sure to explain what you learned from this success.