Java Tutorials - Herong's Tutorial Examples - v8.22, by Herong Yang
System.setProperty() - Setting Your Own Properties
This section provides a tutorial example on how to modify system properties provided by the JVM, and set your own properties into the system property map.
The system properties are actually stored in a map structure, which can also be used by your application program to store your own properties. For example, the following program stores two non-system properties at the beginning, and uses them later in the program:
/* PropertyTest.java
* Copyright (c) HerongYang.com. All Rights Reserved.
*/
public class PropertyTest {
public static void main(String[] a) {
setProgramInfo();
printMessage();
}
public static void setProgramInfo() {
// Modifying a system property
System.setProperty("java.io.tmpdir","c:\\var\\tmp");
// Adding my own properties
System.setProperty("program.name","Property Test");
System.setProperty("program.version","3.01");
}
public static void printMessage() {
String userName = System.getProperty("user.name");
String programName = System.getProperty("program.name");
String programVersion = System.getProperty("program.version");
String ioTempDir = System.getProperty("java.io.tmpdir");
System.out.println("Hello "+userName+",");
System.out.println("");
System.out.println("Welcome to \""+programName+", "
+programVersion+"\".");
System.out.println("Note that the Java I/O "
+" temporary directory is located at "+ioTempDir+".");
}
}
Output:
Hello herong, Welcome to "Property Test, 3.01". Note that the Java I/O temporary directory is located at c:\var\tmp.
Table of Contents
Execution Process, Entry Point, Input and Output
Primitive Data Types and Literals
Bits, Bytes, Bitwise and Shift Operations
Managing Bit Strings in Byte Arrays
Reference Data Types and Variables
StringBuffer - The String Buffer Class
►System Properties and Runtime Object Methods
►System.setProperty() - Setting Your Own Properties
Runtime.getRuntime() - Getting the Runtime Object
freeMemory() - Getting JVM Free Memory Information
Calculating Memory Usage of an Array
exec() - Executing Operating System Commands
Generic Classes and Parameterized Types
Generic Methods and Type Inference
Lambda Expressions and Method References
Java Modules - Java Package Aggregation
Execution Threads and Multi-Threading Java Programs
ThreadGroup Class and "system" ThreadGroup Tree
Synchronization Technique and Synchronized Code Blocks
Deadlock Condition Example Programs
Garbage Collection and the gc() Method
Assert Statements and -ea" Option