Garbage Collection Interview Questions

Question-117: What is Garbage Collection?
Answer:
Garbage collection is a process of reclaiming the runtime unused objects.It is performed for memory management.


Question-118: What is gc()?
Answer:
gc() is a daemon thread.gc() method is defined in System class that is used to send request to JVM to perform garbage collection.


Question-119: What is the purpose of finalize() method?
Answer:
finalize() method is invoked just before the object is garbage collected.It is used to perform cleanup processing.


Question-120: Can an unrefrenced objects be refrenced again?
Answer:
Yes.


Question-121: What kind of thread is the Garbage collector thread?
Answer:
Daemon thread.


Question-122: What is difference between final, finally and finalize?
Answer:

1. final: final is a keyword, final can be variable, method or class.You, can’t change the value of final variable, can’t override final method, can’t inherit final class.
2. finally: finally block is used in exception handling. finally block is always executed.
3. finalize():finalize() method is used in garbage collection.finalize() method is invoked just before the object is garbage collected.The finalize() method can be used to perform any cleanup processing.

Question-123:What is the purpose of the Runtime class?
Answer:
The purpose of the Runtime class is to provide access to the Java runtime system.


Question-124: How will you invoke any external process in Java?
Answer:
By Runtime.getRuntime().exec(?) method.

I/O Interview Questions