void TestParser(String currFile) {
    ASTParser _astParser;
    _astParser = ASTParser.newParser(AST.JLS3);
    _astParser.setKind(ASTParser.K_COMPILATION_UNIT);
    _astParser.setSource(currFile.toCharArray());
    _astParser.setStatementsRecovery(true);
    CompilationUnit cUnit = (CompilationUnit) _astParser.createAST(null);
    cUnit.imports(); /*To test whether cUnit has any data*/
}

//Java Examples 
package org.kodejava.example.util;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class ScannerReadFile {
    public static void main(String[] args) {
        //
        // Create an instance of File for data.txt file.
        //
        File file = new File("data.txt");
        
        try {
            //
            // Create a new Scanner object which will read the data from the 
            // file passed in. To check if there are more line to read from it
            // we check by calling the scanner.hasNextLine() method. We then
            // read line one by one till all line is read.
            //
            Scanner scanner = new Scanner(file);
            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                System.out.println(line);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        
    }
}
 //More examples on java.util

public class Hello {
    public static void main(String[] args) {
        /* some comment inside method
         *  to test,
         */
        int a;
    }
}

  CompilationUnit {
    TypeDeclaration {
      Modifier {
      }
      SimpleName {
      }
      MethodDeclaration {
        Modifier {
        }
        Modifier {
        }
        PrimitiveType {
        }
        SimpleName {
        }
        SingleVariableDeclaration {
          ArrayType {
            SimpleType {
              SimpleName {
              }
            }
          }
          SimpleName {
          }
        }
        Block {
          VariableDeclarationStatement {
            PrimitiveType {
            }
            VariableDeclarationFragment {
              SimpleName {
              }
            }
          }
        }
      }
    }
  }