Configure a Java Application to Use Fiddler

Updated on Nov 6, 2025

===========================================

To configure a Java application to send web traffic to Fiddler, set the proxy using jre:

bash

jre -DproxySet=true -Dhttp.proxyHost=127.0.0.1 -Dhttp.proxyPort=8888

Or:

bash

jre -DproxySet=true -DproxyHost=127.0.0.1 -DproxyPort=8888 MyApp

Or, change the Java Virtual Machine's proxy settings programmatically:

System.setProperty("http.proxyHost", "127.0.0.1");
System.setProperty("https.proxyHost", "127.0.0.1");
System.setProperty("http.proxyPort", "8888");
System.setProperty("https.proxyPort", "8888");

For the seamless experience in Windows you may consider adding

System.setProperty("javax.net.ssl.trustStoreType","Windows-ROOT");

Learn more about Java proxy settings.