Question: What is difference between add() and addElement() in Vector?

Answer: This method is identical in functionality to the add(Object) method (which is part of the List interface).

add(Object ) is due the fact that Vector implements List Interface and it is appeared since Java 1.2 when Vector was moved to Collections: The collection classes from earlier releases, Vector and Hashtable, have been retrofitted to implement the collection interfaces.

addElement is "original" Vector's method....

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Question: How do I find out how long the JVM has been running?

Answer:  A Java virtual machine has a single instance of the implementation class of this interface. This instance implementing this interface is an MXBean (java.lang.management package) that can be obtained by calling the ManagementFactory.getRuntimeMXBean() method or from the platform MBeanServer method.

The ObjectName for uniquely identifying the MXBean for the runtime system within an MBeanServer is:

java.lang:type=Runtime

This interface defines several convenient methods for accessing system properties about the Java virtual machine:

* getBootClassPath()
    Returns the boot class path that is used by the bootstrap class loader to search for class files.
* getClassPath()
    Returns the Java class path that is used by the system class loader to search for class files.
* getInputArguments()
    Returns the input arguments passed to the Java virtual machine which does not include the arguments to the main method.
* getLibraryPath()
    Returns the Java library path.
* getManagementSpecVersion()
    Returns the version of the specification for the management interface implemented by the running Java virtual machine.
* getName()
    Returns the name representing the running Java virtual machine.
* getSpecName()
    Returns the Java virtual machine specification name.
* getSpecVendor()
    Returns the Java virtual machine specification vendor.
* getSpecVersion()
    Returns the Java virtual machine specification version.
* getStartTime()
    Returns the start time of the Java virtual machine in milliseconds.
* getSystemProperties()
    Returns a map of names and values of all system properties.
* getUptime()
    Returns the uptime of the Java virtual machine in milliseconds.
* getVmName()
    Returns the Java virtual machine implementation name.
* getVmVendor()
    Returns the Java virtual machine implementation vendor.
* getVmVersion()
    Returns the Java virtual machine implementation version.
* isBootClassPathSupported()
    Tests if the Java virtual machine supports the boot class path mechanism used by the bootstrap class loader to search for class files.

This tip is based on Java API(1.5)

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