Capturing Traffic from Java Applications

Updated on Nov 11, 2025

The Java Virtual Machine (JVM) has its proxy configuration settings. How can I export the Fiddler root CA (certificate authority) for handling HTTPS traffic and set up the JVM to respect the Fiddler proxy?

Solution

Export the Fiddler Everywhere root CA.
Create a JVM keystore by using the exported certificate and the keytool application. Note that you will need admin access rights to use the keytool application. The following command prompts you to create a password and outputs FiddlerKeystoreFile in the pre-set export path.
Java
```
%JAVA_HOME%\bin\keytool.exe -import -file <path-to-exported-CA>\Fiddler_Root_Certificate_Authority.crt -keystore <your-export-path>\FiddlerKeystoreFile -alias Fiddler
```

Configure the java application to use the Fiddler proxy and certificate through jre.

jre -DproxySet=true -DproxyHost=127.0.0.1 -DproxyPort=8866 -Djavax.net.ssl.trustStore=<your-export-path>\FiddlerKeystoreFile -Djavax.net.ssl.trustStorePassword=<Keystore Password>