Interview Questions.

Q1. What Are The Different Ways To Make An Object Eligible For Garbage Collection When It Is No Longer Needed?

Set all to be had object references to "null" once the motive of creating item is served.

Bundle com.Instanceofjava;

  elegance GarbageCollectionTest1

  public static void fundamental(String [] args)

 String str="garbage series interview questions";

// String item referenced by variable str and isn't always eligible for GC yet.

 Str=null;

//String item referenced by means of variable str is eligible for GC

Make the reference variable to refer to every other item. Decouple the reference variable from the item and set it talk over with any other item, so the item which was relating to earlier than reassigning is eligible for Garbage Collection

bundle com.Instanceofjava;

 magnificence GarbageCollectionTest2

  public static void main(String [] args)

 String str1="rubbish collection interview questions";

String str2="Top 15 garbage collection interview questions";

// String object referenced by means of variable str1 and str2 and isn't eligible for GC yet.

 Str1=str2;

//String item referenced via variable str1 is eligible for GC

 

Q2. When Does An Object Become Eligible For Garbage Collection?

An item turns into eligible for rubbish collection while no stay thread can get right of entry to it.

Q3. How Many Times Does The Garbage Collector Calls The Finalize() Method For An Object?

Only once.

Q4. Can We Force Garbage Collector?

No, we can't pressure rubbish collector to spoil objects , but we are able to request it.

Q5. How To Enable /disable Call Of Finalize() Method Of Exit Of Application?

Runtime.GetRuntime().RunFinalizersOnExit(boolean fee). Passing the boolean fee  proper and false will permit or disable the finalize() name.

Q6. What Is Purpose Of Overriding Finalize() Method?

The finalize() technique must be overridden for an item to encompass the clean up code or to eliminate the device resources that need to to be finished before the item is rubbish accrued.

Q7. So Can You Guarantee Objects Destruction?

No, we cannot guarantee objects destruction even though it is unreferenced, because we can not guarantee garbage collector execution.

So, we can affirm whether item is eligible for rubbish series or no longer.

Q8. How Can We Request Jvm To Start Garbage Collection Process?

We have a method known as gc() in gadget class as static method and also in Runtime class as non static method to request JVM to start garbage collector execution.

System.Gc();

Runtime.GetRuntime().Gc();

Q9. How Jvm Can Destroy Unreferenced Object?

JVM internally uses a daemon thread referred to as "garbage collector" to damage all unreferenced objects.

A daemon thread is a service thread. Garbage Collector thread is referred to as daemon thread as it gives services to JVM to ruin unreferenced items.

This thread is low priority thread. Since it is a low priority thread we can't assure this execution.

Q10. Which Part Of The Memory Is Involved In Garbage Collection?

Heap.

Q11. What Are The Different Ways To Call Garbage Collector?

System.Gc();

Runtime.GetRuntime().Gc();

Q12. What Is The Algorithm Jvm Internally Uses For Destroying Objects?

"mark and change" is the algorithm JVM internally uses.

Q13. What Is Garbage Collection In Java?

Garbage Collection is an automatic memory control function.

The technique of destroying unreferenced objects is called Garbage Collection.

Once object is unreferenced it's miles considered as unused object, hence JVM automatically destroys that item.

In java builders duty is most effective to creating gadgets and unreferencing the ones objects after utilization.

Q14. What Is Responsibility Of Garbage Collector?

Garbage Collector frees the reminiscence occupied by way of the unreachable gadgets during the java software by way of deleting these unreachable objects.

It guarantees that the available memory can be used successfully, but does now not assure that there could be enough reminiscence for this system to run.

Q15. What Happens If An Uncaught Exception Is Thrown From During The Execution Of Finalize() Method Of An Object?

The exception will be overlooked and the garbage series (finalization) of that item terminates