In Java, you can use System.getProperties() to get all the system properties.
Properties properties = System.getProperties();
properties.forEach((k, v) -> System.out.println(k + ":" + v)); // Java 8
1. Example
DisplayApp.java
package com.mkyong.display;
import java.util.Properties;
public class DisplayApp {
public static void main(String[] args) {
Properties properties = System.getProperties();
// Java 8
properties.forEach((k, v) -> System.out.println(k + ":" + v));
// Classic way to loop a map
//for (Map.Entry<Object, Object> entry : properties.entrySet()) {
// System.out.println(entry.getKey() + " : " + entry.getValue());
//}
// No good, output is truncated, long lines end with ...
//properties.list(System.out);
}
}
Output
sun.desktop:windows
awt.toolkit:sun.awt.windows.WToolkit
java.specification.version:10
file.encoding.pkg:sun.io
sun.cpu.isalist:amd64
sun.jnu.encoding:Cp1252
java.class.path:D:\maven-examples\maven-profiles\target\classes;
java.vm.vendor:"Oracle Corporation"
sun.arch.data.model:64
user.variant:
java.vendor.url:http://java.oracle.com/
user.timezone:
os.name:Windows 10
java.vm.specification.version:10
sun.java.launcher:SUN_STANDARD
user.country:MY
sun.boot.library.path:C:\opt\Java\jdk-10\bin
sun.java.command:com.mkyong.password.DisplayApp
jdk.debug:release
sun.cpu.endian:little
user.home:C:\Users\mkyong
user.language:en
java.specification.vendor:Oracle Corporation
java.version.date:2018-04-17
java.home:C:\opt\Java\jdk-10
file.separator:\
java.vm.compressedOopsMode:Zero based
line.separator:
java.specification.name:Java Platform API Specification
java.vm.specification.vendor:Oracle Corporation
java.awt.graphicsenv:sun.awt.Win32GraphicsEnvironment
user.script:
sun.management.compiler:HotSpot 64-Bit Tiered Compilers
java.runtime.version:10.0.1+10
user.name:mkyong
path.separator:;
os.version:10.0
java.runtime.name:Java(TM) SE Runtime Environment
file.encoding:UTF-8
java.vm.name:Java HotSpot(TM) 64-Bit Server VM
java.vendor.version:18.3
java.vendor.url.bug:http://bugreport.java.com/bugreport/
java.io.tmpdir:C:\Users\mkyong\AppData\Local\Temp\
java.version:10.0.1
user.dir:D:\maven-examples\maven-profiles
os.arch:amd64
java.vm.specification.name:Java Virtual Machine Specification
java.awt.printerjob:sun.awt.windows.WPrinterJob
sun.os.patch.level:
java.library.path:C:\opt\Java\jdk-10\bin;C:\WINDOWS\Sun\Java\bin;
java.vendor:Oracle Corporation
java.vm.info:mixed mode
java.vm.version:10.0.1+10
sun.io.unicode.encoding:UnicodeLittle
java.class.version:54.0
Process finished with exit code 0
2. Sorting
Example to display all the system properties in Alphabetical order.
DisplayApp.java
package com.mkyong.display;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Properties;
import java.util.stream.Collectors;
public class DisplayApp {
public static void main(String[] args) {
Properties properties = System.getProperties();
// Thanks Java 8
LinkedHashMap<String, String> collect = properties.entrySet().stream()
.collect(Collectors.toMap(k -> (String) k.getKey(), e -> (String) e.getValue()))
.entrySet().stream().sorted(Map.Entry.comparingByKey())
.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue,
(oldValue, newValue) -> oldValue, LinkedHashMap::new));
collect.forEach((k, v) -> System.out.println(k + ":" + v));
}
}
Output
awt.toolkit:sun.awt.windows.WToolkit
file.encoding:UTF-8
file.encoding.pkg:sun.io
file.separator:\
java.awt.graphicsenv:sun.awt.Win32GraphicsEnvironment
java.awt.printerjob:sun.awt.windows.WPrinterJob
//...
sun.cpu.endian:little
sun.cpu.isalist:amd64
sun.desktop:windows
sun.io.unicode.encoding:UnicodeLittle
sun.java.command:com.mkyong.password.DisplayApp
sun.java.launcher:SUN_STANDARD
sun.jnu.encoding:Cp1252
sun.management.compiler:HotSpot 64-Bit Tiered Compilers
sun.os.patch.level:
user.country:MY
user.dir:D:\maven-examples\maven-profiles
user.home:C:\Users\mkyong
user.language:en
user.name:mkyong
user.script:
user.timezone:
user.variant:
Here’s a much simpler away to sort:
TreeMap map = new TreeMap(properties);
map.forEach((k, v) -> System.out.println(k + ” = ” + v));
May be a little more simpler solution for #2 Sorting example:
SortedMap sortedMap = new TreeMap();
properties.entrySet().stream().forEach(entry -> sortedMap.put(entry.getKey().toString(), entry.getValue().toString()));
sortedMap.forEach((k, v) -> System.out.println(k + “:” + v));
Prefer the -XX:+PrintFlagsFinal way!
This output is truncated, though. Some lines end in “…” instead of the rest of that property. Not so useful.
Article is updated, use below code to print the complete lines.
properties.forEach((k, v) -> System.out.println(k + “:” + v));
Hi,
just wanted to say that I like your blog.
I’m not a coder, I’m an infrastructure guy and I found your posts very useful for Java tips which I need for a JMX monitoring tool that I’m writing.
Keep up the good work.
Regards,
Bob
Hi Bob
Did you write JMX bean for the system propertieS?
Regards
Nishant