Using Fiddler with MSAL Java

You can use the MSAL4J with a proxy such as Fiddler to debug requests and responses.

1. Set up a keystore file

• From Fiddler, export FiddlerRoot.cer to desktop via Tools -> Options -> HTTPS -> Actions button
• Open Command Prompt as an admin
• Run JDK's keytool to create a keystore

<JDK_HOME>\bin\keytool.exe -import -file C:\Users\<username>\Desktop\FiddlerRoot.cer^ -keystore FiddlerKeystore -alias Fiddler

• Enter a password for your keystore. Make sure to remember this as you will need it later on.

2a. Set up IntelliJ

• In IntelliJ, open Run/Debug configurations
• Create a new debug configuration called “Fiddler Trace”
• Add the following VM Options:

-DproxySet=true -DproxyHost=127.0.0.1 -DproxyPort=8888 -Djavax.net.ssl.trustStorePassword="yourpassword" -Djavax.net.ssl.trustStore="path\to\keystore\FiddlerKeystore"

2b. Set up Eclipse

• In Eclipse, open Run -> Run Configurations
• Select the Run Configuration you want to use
• Select the Arguments tab
• Add the following arguments:

-DproxySet=true -DproxyHost=127.0.0.1 -DproxyPort=8888 -Djavax.net.ssl.trustStore="path\to\keystore\FiddlerKeystore" -Djavax.net.ssl.trustStorePassword="yourpassword"