Answer: Runtime.getRuntime().freeMemory() : Questions « Utility Classes « SCJP

A

public class MainClass{
    public static void main(String[] argv){
       System.out.println(Runtime.getRuntime().freeMemory());
    }
}

8.31.Questions
	8.31.1.	Which collection allows you to grow or shrink its size and provides indexed access to its elements, but whose methods are not synchronized?
	8.31.2.	Answer: collection
	8.31.3.	What is the result(PriorityQueue)?
	8.31.4.	Answer: PriorityQueue
	8.31.5.	What is the output(TreeSet and sub set)?
	8.31.6.	Answer: TreeSet and sub set
	8.31.7.	What is the output(TreeMap and ceiling keys)?
	8.31.8.	Answer: TreeMap and ceiling keys
	8.31.9.	Which, inserted independently at line 9, will compile? (Choose all that apply.)
	8.31.10.	Answer: generic and hierarchy
	8.31.11.	What is the result(TreeSet)?
	8.31.12.	Answer: TreeSet and class hierarchy
	8.31.13.	What is the output(implements Comparator)?
	8.31.14.	Answer: implements Comparator
	8.31.15.	Instances of which class(es) can be serialized?
	8.31.16.	Answer: serizlizable objects
	8.31.17.	What is the output(NumberFormat)?
	8.31.18.	Answer: NumberFormat
	8.31.19.	What is the result(pattern matching)?
	8.31.20.	Answer: pattern matching
	8.31.21.	What is the result(Scanner)?
	8.31.22.	Answer: Scanner
	8.31.23.	Which of the following suggested changes will allow the method to compile?
	8.31.24.	Answer: Boolean and if statement
	8.31.25.	You must initialize java.lang.System class if you want to use the System.err output(True/False).
	8.31.26.	Answer: java.lang.System
	8.31.27.	The System.arraycopy method works only with arrays of primitives(True/False).
	8.31.28.	Answer: System.arraycopy method
	8.31.29.	The System.exit method takes an int primitive parameter(True/False).
	8.31.30.	Answer: System.exit method
	8.31.31.	There is a Runtime method to request that the JVM start garbage collection(True/False).
	8.31.32.	Answer: Runtime method
	8.31.33.	long avail = Runtime.getRuntime().freeMemory() returns the approximate amount of free memory available to the JVM(True/False)
	8.31.34.	Answer: Runtime.getRuntime().freeMemory()
	8.31.35.	A Vector can hold object references or primitive values(True/False).
	8.31.36.	Answer: Vector and primitive values
	8.31.37.	A Vector maintains object references in the order they were added(True/False).
	8.31.38.	Answer: Vector and inserted order