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- The pace at which javac/JDK moves and at which NetBeans moves is simply different. E.g., imagine a refactoring breaking a user's code because of error recovery misbehaving. Once the problem is found it may be fixed in nb-javac in hours or days. Fixing it in javac can easily take weeks or even months (and much more effort in testing and review).
- Even some changes that from the NetBeans point may look innocent may be hard to get into vanilla javac. For example, when javac detects a syntax error, it normally ends without getting to a semantic analysis. This does not work for an IDE (noone probably wants to lose almost all features just because a semicolon is missing). But it may be difficult to push through a fix to semantic analysis for a syntactically broken code (sometimes this passed before, other times, there was a pushback on such changes, depending on the nature of the change needed).
- Some of the changes in nb-javac may be very hard to get in unless it has another user than just NetBeans.
Taking a step back, what are the potential alternative Java parsing libraries to support
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the optional module for Java in NetBeans?
- Write a new library/compiler. Not quite realistic.
- Use some other than javac (like from Eclipse). Not sure what would be the differentiator between Eclipse and NetBeans? Would result in incompatible changes and probably almost a complete re-write of the existing Java support in NetBeans (unless the Java support itself would be taken from Eclipse as well, which aside from everything else would be a lot of rework too).
- Use a vanilla (unpatched) javac from the current runtime JDK. Besides other complexities, one would need to run on JDK 9 to get the possibility of JDK 9 support (and on, e.g., Valhalla to get the possibility of having Valhalla support), which might possibly lead to workarounds for differences/bugs between JDK versions. Plus, we might run into trouble with strong encapsulation.
- Use a vanilla (unpatched) javac corresponding to a particular revision from the OpenJDK, but let NetBeans have a firm (binary) copy against which it would run, regardless of which runtime JDK would be used. Still a significant endeavour.
- Keep nb-javac as it is now. Certainly the least amount of work and complexity.
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