java.lang
Class Runtime

java.lang.Object
  extended by java.lang.Runtime

@TransactionType(value=NOT_SUPPORTED)
public class Runtime
extends Object

Every Java application has a single instance of class Runtime that allows the application to interface with the environment in which the application is running. The current runtime can be obtained from the getRuntime method.

An application cannot create its own instance of this class.

This Java Card class is a subset of the CLDC 1.1 Runtime class. Some interfaces, methods and/or variables have been pruned, and/or other methods simplified, in an effort to reduce the size of this class and/or eliminate dependencies on unsupported features.

Since:
JDK1.0, CLDC 1.0, Java Card 3.0
See Also:
getRuntime()

Method Summary
 long freeMemory()
          Returns the amount of free memory in the system.
 void gc()
          Runs the garbage collector.
static Runtime getRuntime()
          Returns the runtime object associated with the current Java application.
 long totalMemory()
          Returns the total amount of memory in the Java Virtual Machine.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Method Detail

getRuntime

public static Runtime getRuntime()
Returns the runtime object associated with the current Java application. Most of the methods of class Runtime are instance methods and must be invoked with respect to the current runtime object.

Returns:
the Java Card RE-owned Runtime object associated with the current Java application.

freeMemory

public long freeMemory()
Returns the amount of free memory in the system. Calling the gc method may result in increasing the value returned by freeMemory.

Returns:
an approximation to the total amount of memory currently available for future allocated objects, measured in bytes.

totalMemory

public long totalMemory()
Returns the total amount of memory in the Java Virtual Machine. The value returned by this method may vary over time, depending on the host environment.

Note that the amount of memory required to hold an object of any given type may be implementation-dependent.

Returns:
the total amount of memory currently available for current and future objects, measured in bytes.

gc

public void gc()
Runs the garbage collector. Calling this method suggests that the Java Virtual Machine expend effort toward recycling unused objects in order to make the memory they currently occupy available for quick reuse. When control returns from the method call, the Java Virtual Machine has made its best effort to recycle all discarded objects.

The name gc stands for "garbage collector". The Java Virtual Machine performs this recycling process automatically as needed even if the gc method is not invoked explicitly.

The method System.gc() is the conventional and convenient means of invoking this method.



Copyright (c) 2009 Sun Microsystems, Inc. All rights reserved.