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Default Value

false

java.net.useSystemProxies Overview

When set to true Java networking classes (java.net) will attempt to use proxies defined by the operating system.

This property is supported on Windows, Mac OSX and on Linux when configured through Gnome 2.x.

The java.net.useSystemProxies property is only checked once during startup.

Related System Properties

Here are some other networking Java system properties:

• http.agent
• http.keepAlive
• http.maxConnections
• https.protocols
• java.net.preferIPv4Stack
• java.net.preferIPv6Addresses
• javax.net.debug
• javax.net.ssl.trustStore
• jdk.net.hosts.file
• jdk.tls.client.protocols
• jdk.tls.disabledAlgorithms
• networkaddress.cache.negative.ttl
• networkaddress.cache.ttl
• sun.net.client.defaultConnectTimeout
• sun.net.client.defaultReadTimeout
• sun.net.inetaddr.ttl

Supported Since

Java has supported the java.net.useSystemProxies system property since at least version 8, support may go back to even older versions of java.

Setting java.net.useSystemProxies on Startup

You can set the java.net.useSystemProxies java system property during startup of the java runtime using the -D command line argument:

java -Djava.net.useSystemProxies=true MyAppMain

You may also be able to specify java.net.useSystemProxies via the JAVA_TOOL_OPTIONS environment variable:

JAVA_TOOL_OPTIONS=-Djava.net.useSystemProxies=true

Setting / Reading java.net.useSystemProxies at Runtime

You can set java.net.useSystemProxies at runtime with the following Java code:

System.setProperty("java.net.useSystemProxies", "true");

WARNING: Depending on the property and JVM version using setProperty may or may not work if the JDK Java class that uses this variable has already been loaded. The value of the java.net.useSystemProxies system property may be cached within an internal private static variable of the implementing class.

To read the value of java.net.useSystemProxies at runtime, you can use this Java code:

String propertyValue = System.getProperty("java.net.useSystemProxies");
if (propertyValue != null) {
    System.out.println("java.net.useSystemProxies = " + propertyValue);
} else {
    System.out.println("java.net.useSystemProxies was null");
}

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