Utilice JDT ASTParser para analizar archivos .java individuales

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.HashSet;
import java.util.Set;
 
import org.eclipse.jdt.core.dom.AST;
import org.eclipse.jdt.core.dom.ASTParser;
import org.eclipse.jdt.core.dom.ASTVisitor;
import org.eclipse.jdt.core.dom.CompilationUnit;
import org.eclipse.jdt.core.dom.SimpleName;
import org.eclipse.jdt.core.dom.VariableDeclarationFragment;
 
public class Main {
 
	//use ASTParse to parse string
	public static void parse(String str) {
		ASTParser parser = ASTParser.newParser(AST.JLS3);
		parser.setSource(str.toCharArray());
		parser.setKind(ASTParser.K_COMPILATION_UNIT);
 
		final CompilationUnit cu = (CompilationUnit) parser.createAST(null);
 
		cu.accept(new ASTVisitor() {
 
			Set names = new HashSet();
 
			public boolean visit(VariableDeclarationFragment node) {
				SimpleName name = node.getName();
				this.names.add(name.getIdentifier());
				System.out.println("Declaration of '" + name + "' at line"
						+ cu.getLineNumber(name.getStartPosition()));
				return false; // do not continue 
			}
 
			public boolean visit(SimpleName node) {
				if (this.names.contains(node.getIdentifier())) {
					System.out.println("Usage of '" + node + "' at line "
							+ cu.getLineNumber(node.getStartPosition()));
				}
				return true;
			}
		});
 
	}
 
	//read file content into a string
	public static String readFileToString(String filePath) throws IOException {
		StringBuilder fileData = new StringBuilder(1000);
		BufferedReader reader = new BufferedReader(new FileReader(filePath));
 
		char[] buf = new char[10];
		int numRead = 0;
		while ((numRead = reader.read(buf)) != -1) {
			System.out.println(numRead);
			String readData = String.valueOf(buf, 0, numRead);
			fileData.append(readData);
			buf = new char[1024];
		}
 
		reader.close();
 
		return  fileData.toString();	
	}
 
	//loop directory to get file list
	public static void ParseFilesInDir() throws IOException{
		File dirs = new File(".");
		String dirPath = dirs.getCanonicalPath() + File.separator+"src"+File.separator;
 
		File root = new File(dirPath);
		//System.out.println(rootDir.listFiles());
		File[] files = root.listFiles ( );
		String filePath = null;
 
		 for (File f : files ) {
			 filePath = f.getAbsolutePath();
			 if(f.isFile()){
				 parse(readFileToString(filePath));
			 }
		 }
	}
 
	public static void main(String[] args) throws IOException {
		ParseFilesInDir();
	}
}