How to use ssl.log for TLS_DHE_RSA_WITH_AES_128_CBC_SHA?

Question

Encryption

As you know, firefox can be forced to log the key (environment parameter SSLKEYLOGFILE), then it will write data like this to the specified file:
CLIENT_RANDOM <64 bytes of hex encoded client_random> <96 bytes of hex encoded master secret> The
question is simple, if TLS_DHE_RSA_WITH_AES_128_CBC_SHA is used, then the AES algorithm is used with a 128-bit key, but a long string of 96 bytes is still written in the log, the question is how to get the key to decrypt the traffic.
I'm trying to decrypt traffic using a JAVA application.