If you are not familiar with how WebSphere integrates with Java, refer to Getting Started with Java on WebSphere.

The managesdk.bat (Windows) or managesdk.sh (Linux) command with the -setNewProfileDefault option will update a profile to use a certain version of Java SDK by default. The -getNewProfileDefault option can be used to determine the version of Java SDK that will be used when a new profile is created.

Before using the -setNewProfileDefault option so that new profiles will use a certain version of Java SDK, you may want to use the -listEnabledProfileAll option to list the version of Java SDK being used by the profile, node, and servers, and -enableProfile or -enableProfileAll to update a profile, node, and servers to use a certain version of Java SDK.

AVOID TROUBLE

If you are prompted for a username and password, refer to username password and the soap.client.props sas.client.props ipc.client.props files.

${WAS_INSTALL_ROOT}/bin/managesdk.sh -setNewProfileDefault -sdkname 1.8_64

When starting your WebSphere network deployment manager (dmgr), node, or application server, the HPEL or SystemOut log should contain something like this, where the Java version matches the Java version being returned by the managesdk command.

Java version = 1.8.0_211, Java Runtime Version = 8.0.5.37 - pxa6480sr5fp37-20190618_01(SR5 FP37), Java Compiler = j9jit29, Java VM name = IBM J9 VM
Java Home = /opt/WebSphere/AppServer90/java/jre