- Java.lang Package classes
- Java.lang - Home
- Java.lang - Boolean
- Java.lang - Byte
- Java.lang - Character
- Java.lang - Character.Subset
- Java.lang - Character.UnicodeBlock
- Java.lang - Class
- Java.lang - ClassLoader
- Java.lang - Compiler
- Java.lang - Double
- Java.lang - Enum
- Java.lang - Float
- Java.lang - InheritableThreadLocal
- Java.lang - Integer
- Java.lang - Long
- Java.lang - Math
- Java.lang - Number
- Java.lang - Object
- Java.lang - Package
- Java.lang - Process
- Java.lang - ProcessBuilder
- Java.lang - Runtime
- Java.lang - RuntimePermission
- Java.lang - SecurityManager
- Java.lang - Short
- Java.lang - StackTraceElement
- Java.lang - StrictMath
- Java.lang - String
- Java.lang - StringBuffer
- Java.lang - StringBuilder
- Java.lang - System
- Java.lang - Thread
- Java.lang - ThreadGroup
- Java.lang - ThreadLocal
- Java.lang - Throwable
- Java.lang - Void
- Java.lang Package extras
- Java.lang - Interfaces
- Java.lang - Errors
- Java.lang - Exceptions
- Java.lang Package Useful Resources
- Java.lang - Useful Resources
- Java.lang - Discussion
Java.lang.System.getProperty() Method
Description
The java.lang.System.getProperty(String key, String def) method gets the system property indicated by the specified key.The argument def is the default value.
Declaration
Following is the declaration for java.lang.System.getProperty() method
public static String getProperty(String key, String def)
Parameters
key − This is the name of the system property.
def − This is a default value.
Return Value
This method returns the string value of the system property, or null if there is no property with that key.
Exception
SecurityException − if a security manager exists and its checkPropertyAccess method doesn't allow access to the specified system property.
NullPointerException − if key is null.
IllegalArgumentException − if key is empty.
Example
The following example shows the usage of java.lang.System.getProperty() method.
package com.tutorialspoint; import java.lang.*; public class SystemDemo { public static void main(String[] args) { // gets the system property System.out.println(System.getProperty("string","defaultPassword")); } }
Let us compile and run the above program, this will produce the following result −
defaultPassword
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