Update java.md

Adding the Semeru JDK information, additionally updating our docs for more of our current JDK providers information which was missing

Author: smokodon

user/languages/java.md

@@ -227,6 +227,17 @@ script:
 ```
 {: data-file=".travis.yml"}
 
+## Current JDK providers
+
+Currently our builds are using Bellsoft and Adoptium JDK providers - they are switched based on the distribution and architecture you are using in your build. Additionally, we've added IBM's Semeru JDK - to use it, instead of using jdk: jdkX or jdk: openjdkX syntax, simply use jdk: semeruX like here:
+```yaml
+language: java
+jdk: semeru11
+```
+{: data-file=".travis.yml"}
+
+Available semeru JDKs for AMD, S390X, PPC64LE and ARM architectures: 8, 11, 16, 17, 18, 19, 20, 21, 22
+
 ## Examples
 
 - [JRuby](https://github.com/jruby/jruby/blob/master/.travis.yml)