Develop Reference

PL/SQL source code parser (in Java)

I'm looking for general purpose source parser in Java.
Library which can help me to parser PL/SQL code. Extract functions, procedures, packages and show dependencies between them.

Consider looking at ANTLR tool. There exist already PL/SQL grammar. Please spend some time for reading about this tool. It should surely solve your problem.

There is a plsql-parser on GitHub, quote:
This is a [almost] full parser for PL/SQL language that includes a Lexer, Parser (that optionally generates an Abstract Syntax Tree) and a TreeWalker. Current version is target for Java language, but may be easy to port it to any other target.
I am interested in porting PL/SQL data structures to Java and will try it the next weeks.
Another option could be https://stackoverflow.com/a/6631453/734687, but note that you have to port the target language from C to Java.

Java to HTML Parser / State Machine

I wish to create a app that translates input java code into HTML formatted java code,
For example:
public class ReadWithScanner
Would become
<span class="public">public</span> <span class="class">class</span> ReadWithScanner
However it gets quite complicated when it comes to parameters and regular expressions. Now I have a bit of time on my hands, and I wish to write my own code parser.
How would I start this? and is there any tutorials or online content to not only help me write this, but understand it.
Thanks

For help with the complexity of parsing, you'll need to rely on the Java Language Specification.
As I seem to recall, Java is an LL(k) language (see here, for instance). However, the Java language, despite all attempts to keep it "compact", is still quite large and complex. The grammar is spread out over the entire document. This is not a project for the faint at heart. You might consider using a Java parsing tool (like Java-front).

What you need to do is use ANTLR, it already has Java grammars for parsing Java, then you just need to supply your own templates to output whatever you want from the Abstract Syntax Tree you generate with ANTLR.

If you need a resource for learning about parsers, I can recommend Basics of Compiler Design, which is available as a free download.
It covers more than just parsers, but if you read the first few chapters, you should have a good basic understanding of both lexers and parsers.

I think you need a lexical analyzer.
I used early the Flex lexical analyzer. It is not too complicated to use.
If you need to parse the analyzed text you can use the bison c++
bisoncpp.sourceforge.net/
(C++ konwledge need and linux environment)

Ruby parser in Java

The project I'm doing is written in Java and parsers source code files. (Java src up to now). Now I'd like to enable parsing Ruby code as well.
Therefore I am looking for a parser in Java that parses Ruby source code.
The only thing I have been able to find up to now are Ruby parsers in Ruby (ParseTree and RubyParser...).
I could maybe parse the source files I want with a Ruby parser in JRuby, and then access my Java stuff from there.
But that would mean that I will not be able to reuse a lot of my previously written Java code.
Is there a decent Ruby parser in Java out there and have I just not be able to find it? Or does someone see a better solution?

See http://kenai.com/projects/jruby-parser/

You could let ANTLR generate a lexer/parser for you. They have a simplified Ruby grammar available: http://www.antlr.org/grammar/1160820213459/rubyParserLexerSPGrammar.g which may be sufficient for your needs.

Yacc equivalent for Java

I'm working on a compiler design project in Java. Lexical analysis is done (using jflex) and I'm wondering which yacc-like tool would be best(most efficient, easiest to use, etc.) for doing syntactical analysis and why.

If you specifically want YACC-like behavior (table-driven), the only one I know is CUP.
In the Java world, it seems that more people lean toward recursive descent parsers like ANTLR or JavaCC.
And efficiency is seldom a reason to pick a parser generator.

In the past, I've used ANLTR for both lexer and parser, and the JFlex homepage says it can interoperate with ANTLR. I wouldn't say that ANTLR's online documentation is that great. I ended up investing in 'The Definitive ANTLR reference', which helped considerably.

GNU Bison has a Java interface,
http://www.gnu.org/software/bison/manual/html_node/Java-Bison-Interface.html
You can use it go generate Java code.

There is also jacc.
Jacc is about as close to yacc as you can get, but it is implemented in pure java and generates a java parser.
It interfaces well with jFlex
http://web.cecs.pdx.edu/~mpj/jacc/

Another option would be the GOLD Parser.
Unlike many of the alternatives, the GOLD parser generates the parsing tables from the grammar and places them in a binary, non-executable file. Each supported language then has an engine which reads the binary tables and parses your source file.
I've not used the Java implementation specifically, but have used the Delphi engine with fairly good results.

What's the best tool for generating a parser in Java for my own language grammar?

I'm developing a small programming language based mostly of the C99 standard and I've already written a fairly decent lexer in java and now I'm looking to generate a Java Parser from the grammar. I know there's Bison, but that seems to only generate C code. I'm looking for a application that will allow me to input my grammar and create a full parser class in java code. Reading other SO posts on related topics, I've found ANTLR, but I'm wondering if anyone in the SO knows about a better tool?
thanks!

Another couple to look at are JavaCC and SableCC (it has been a long time since I looked at SableCC).

I've been quite impressed by BNFC, which is able to generate parsers in Java as well as in C, C++, C#, F#, Haskell, and OCaml.

The JFlex home page at http://jflex.de indicates where to find Bison-like tools that can target Java:
http://byaccj.sourceforge.net/
http://www2.cs.tum.edu/projects/cup/
http://www.antlr.org/