Java J2ee Planet

The Java runtime environment deletes objects when it determines that they are no longer being used. This process is known as garbage collection. The Java runtime environment supports a garbage collector that periodically frees the memory used by objects that are no longer needed. The Java garbage collector is a mark-sweep garbage collector that scans Java's dynamic memory areas for objects, marking those that are referenced. After all possible paths to objects are investigated, those objects that are not marked (i.e. are not referenced) are known to be garbage and are collected. (A more complete description of our garbage collection algorithm might be "A compacting, mark-sweep collector with some conservative scanning".) The garbage collector runs synchronously when the system runs out of memory, or in response to a request from a Java program. Your Java program can ask the garbage collector to run at any time by calling System.gc(). The garbage collector requires abou...

Q1) Which part of the memory is involved in Garbage Collection? Stack or Heap? Ans) Heap Q2)What is responsiblity of Garbage Collector? Ans) Garbage collector frees the memory occupied by the unreachable objects during the java program by deleting these unreachable objects. It ensures that the available memory will be used efficiently, but does not guarantee that there will be sufficient memory for the program to run. Q3) Is garbage collector a dameon thread? Ans) Yes GC is a dameon thread. A dameon thread runs behind the application. It is started by JVM. The thread stops when all non-dameon threads stop. Q4)Garbage Collector is controlled by whom? Ans) The JVM controls the Garbage Collector; it decides when to run the Garbage Collector. JVM runs the Garbage Collector when it realizes that the memory is running low, but this behavior of jvm can not be guaranteed. One can request the Garbage Collection to happen f...