ECJ based parsing

Context

Since version 6.0.0 of the Java analyzer (December 2019), the parsing of java source files is done using the Eclipse Compiler for Java (ECJ), itself shipped as part of the eclipse JDT Core project from the eclipse foundation.

Ultimately, this means that the java analyzer's capacity to parse a given version of Java depends merely on the capacity of the eclipse compiler itself to parse this version. In other words, the support of new versions of java depends on the release lifecycle of the JDT.