Java Java 8 API - https://docs.oracle.com/javase/8/docs/api/ Java 9 API - https://docs.oracle.com/javase/9/docs/api/overview-summary.html Java 10 API -https://docs.oracle.com/javase/10/docs/api/overview-summary.html Java 11 API -  N/A Apache Commons - https://commons.apache.org/ Common lang (3.9) - https://commons.apache.org/proper/commons-lang/javadocs/api-3.9/index.html   Common lang (2.6) - https://commons.apache.org/proper/commons-lang/javadocs/api-2.6/index.html