diff --git a/src/main/java/gr/gousiosg/javacg/stat/ClassVisitor.java b/src/main/java/gr/gousiosg/javacg/stat/ClassVisitor.java
index e03d72c6..d3ca0ae0 100644
--- a/src/main/java/gr/gousiosg/javacg/stat/ClassVisitor.java
+++ b/src/main/java/gr/gousiosg/javacg/stat/ClassVisitor.java
@@ -28,58 +28,182 @@
 
 package gr.gousiosg.javacg.stat;
 
-import org.apache.bcel.classfile.Constant;
-import org.apache.bcel.classfile.ConstantPool;
-import org.apache.bcel.classfile.EmptyVisitor;
-import org.apache.bcel.classfile.JavaClass;
-import org.apache.bcel.classfile.Method;
+import org.apache.bcel.classfile.*;
 import org.apache.bcel.generic.ConstantPoolGen;
 import org.apache.bcel.generic.MethodGen;
 
+import java.io.PrintStream;
+
 /**
  * The simplest of class visitors, invokes the method visitor class for each
  * method found.
  */
 public class ClassVisitor extends EmptyVisitor {
 
+    private static final String OBJECT = Object.class.getName();
+    private static final String ENUMERATION = Enum.class.getName();
     private JavaClass clazz;
     private ConstantPoolGen constants;
     private String classReferenceFormat;
-    
-    public ClassVisitor(JavaClass jc) {
+    private PrintStream output;
+    private FormatEnumaration format;
+    private ConstantPool currentConstantPool;
+
+    public ClassVisitor(JavaClass jc, PrintStream outputStream, FormatEnumaration format) {
         clazz = jc;
+        this.format = format;
+        this.output = outputStream;
         constants = new ConstantPoolGen(clazz.getConstantPool());
-        classReferenceFormat = "C:" + clazz.getClassName() + " %s";
+        switch (format) {
+            case TXT:
+                classReferenceFormat = "C:" + clazz.getClassName() + " %s";
+                break;
+            case XML:
+                classReferenceFormat = "<constant tag=\"%s\">%s</constant>";
+                break;
+            default:
+                throw new RuntimeException("Unsupported format "+format);
+        }
+
     }
 
     public void visitJavaClass(JavaClass jc) {
+        switch (format) {
+            case XML:
+                output.println("<class name=\""+jc.getClassName()+"\">");
+                String[] names = jc.getInterfaceNames();
+                if (names != null && names.length>0) {
+                    output.println("<interfaces>");
+                    for (String name:names) {
+                        output.print("<interface>");
+                        output.print(name);
+                        output.println("</interface>");
+                    }
+                    output.println("</interfaces>");
+                }
+                if (OBJECT.equals(jc.getSuperclassName())==false) {
+                    output.print("<super>");
+                    output.print(jc.getSuperclassName());
+                    output.println("</super>");
+                }
+                break;
+        }
         jc.getConstantPool().accept(this);
         Method[] methods = jc.getMethods();
-        for (int i = 0; i < methods.length; i++)
+        for (int i = 0; i < methods.length; i++) {
             methods[i].accept(this);
+        }
+        switch (format) {
+            case XML:
+                output.println("</class>");
+                break;
+        }
     }
 
     public void visitConstantPool(ConstantPool constantPool) {
-        for (int i = 0; i < constantPool.getLength(); i++) {
-            Constant constant = constantPool.getConstant(i);
-            if (constant == null)
-                continue;
-            if (constant.getTag() == 7) {
-                String referencedClass = 
-                    constantPool.constantToString(constant);
-                System.out.println(String.format(classReferenceFormat,
-                        referencedClass));
-            }
+        switch (format) {
+            case TXT:
+                for (int i = 0; i < constantPool.getLength(); i++) {
+                    Constant constant = constantPool.getConstant(i);
+                    if (constant == null)
+                        continue;
+                    if (constant.getTag() == 7) {
+                        String referencedClass =
+                                constantPool.constantToString(constant);
+                        output.println(String.format(classReferenceFormat,
+                                referencedClass));
+                    }
+                }
+            case XML:
+                for (int i = 0; i < constantPool.getLength(); i++) {
+                    Constant constant = constantPool.getConstant(i);
+                    if (constant == null)
+                        continue;
+                    if (constant.getTag() == 7) {
+                        output.print("<constant index=\"");
+                        output.print(i);
+                        output.print("\">");
+                        String referencedClass =
+                                constantPool.constantToString(constant);
+                        output.print(xmlEscapeText(referencedClass));
+                        output.println("</constant>");
+                    }
+                }
         }
     }
 
     public void visitMethod(Method method) {
         MethodGen mg = new MethodGen(method, clazz.getClassName(), constants);
-        MethodVisitor visitor = new MethodVisitor(mg, clazz);
+        MethodVisitor visitor = new MethodVisitor(mg, clazz,output,format);
         visitor.start(); 
     }
 
     public void start() {
         visitJavaClass(clazz);
     }
+
+    /**
+     * Encode special charaters for XML
+     * @param t
+     * @return
+     */
+    static String xmlEscapeText(String t) {
+        StringBuilder sb = null;
+        for(int i = 0; i < t.length(); i++){
+            char c = t.charAt(i);
+            switch(c){
+                case '<':
+                    if (sb==null) {
+                        sb = new StringBuilder(t.length()+10);
+                        sb.append(t.substring(0,i));
+                    }
+                    sb.append("&lt;");
+                    break;
+                case '>':
+                    if (sb==null) {
+                        sb = new StringBuilder(t.length()+10);
+                        sb.append(t.substring(0,i));
+                    }
+                    sb.append("&gt;");
+                    break;
+                case '\"':
+                    if (sb==null) {
+                        sb = new StringBuilder(t.length()+10);
+                        sb.append(t.substring(0,i));
+                    }
+                    sb.append("&quot;");
+                    break;
+                case '&':
+                    if (sb==null) {
+                        sb = new StringBuilder(t.length()+10);
+                        sb.append(t.substring(0,i));
+                    }
+                    sb.append("&amp;");
+                    break;
+                case '\'':
+                    if (sb==null) {
+                        sb = new StringBuilder(t.length()+10);
+                        sb.append(t.substring(0,i));
+                    }
+                    sb.append("&apos;");
+                    break;
+                default:
+                    if(c>0x7e || c<0x20) {
+                        if (sb==null) {
+                            sb = new StringBuilder(t.length()+10);
+                            sb.append(t.substring(0,i));
+                        }
+                        sb.append("&#"+((int)c)+";");
+                    }else if (sb != null) {
+                        sb.append(c);
+                    }
+            }
+        }
+        if (sb==null) {
+            //re-use original string
+            return t;
+        } else {
+            return sb.toString();
+        }
+    }
 }
diff --git a/src/main/java/gr/gousiosg/javacg/stat/FormatEnumaration.java b/src/main/java/gr/gousiosg/javacg/stat/FormatEnumaration.java
new file mode 100644
index 00000000..c9afc34a
--- /dev/null
+++ b/src/main/java/gr/gousiosg/javacg/stat/FormatEnumaration.java
@@ -0,0 +1,5 @@
+package gr.gousiosg.javacg.stat;
+
+public enum FormatEnumaration {
+    TXT,XML
+}
diff --git a/src/main/java/gr/gousiosg/javacg/stat/JCallGraph.java b/src/main/java/gr/gousiosg/javacg/stat/JCallGraph.java
index 4d19408d..88af3917 100644
--- a/src/main/java/gr/gousiosg/javacg/stat/JCallGraph.java
+++ b/src/main/java/gr/gousiosg/javacg/stat/JCallGraph.java
@@ -29,8 +29,12 @@
 package gr.gousiosg.javacg.stat;
 
 import java.io.File;
+import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.PrintStream;
+import java.util.ArrayList;
 import java.util.Enumeration;
+import java.util.List;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
 
@@ -46,9 +50,90 @@
 public class JCallGraph {
 
     public static void main(String[] args) {
+        FormatEnumaration format = FormatEnumaration.TXT;
+        PrintStream outputStream = System.out;
+        List<String> jars = new ArrayList<>(args.length);
+        if (args.length==0) {
+            printHelp();
+        }
+        for (int i =0;i<args.length;i++) {
+            String arg = args[i];
+            if (arg.startsWith("-")) {
+                //additional parameters
+                switch (arg) {
+                    case "-out" :
+                    case "-o" :
+                        File file = new File(args[++i]);
+                        if (file.exists()) {
+                            if (file.isFile()==false) {
+                                System.err.println(args[i]+" is not a file");
+                                System.exit(-1);
+                            }
+                            if (file.canWrite()==false) {
+                                System.err.println("Cannot write to "+args[i]);
+                                System.exit(-1);
+                            }
+                        } else {
+                            try {
+                                file.createNewFile();
+                            } catch (IOException e) {
+                                System.err.println("Cannot create file "+args[i]);
+                                System.err.println(e.getMessage());
+                                System.exit(-1);
+                            }
+                        }
+                        try {
+                            outputStream = new PrintStream(file);
+                        } catch (FileNotFoundException e) {
+                            System.err.println("Cannot create file "+args[i]);
+                            System.err.println(e.getMessage());
+                            System.exit(-1);
+                        }
+                        break;
+                    case "-f" :
+                    case "-format" :
+                        if (i+1<args.length) {
+                            String form = args[++i].toLowerCase();
+                            switch (form) {
+                                case "txt":
+                                    format = FormatEnumaration.TXT;
+                                    break;
+                                case "xml":
+                                    format = FormatEnumaration.XML;
+                                    break;
+                                default:
+                                    System.err.println("Unsupported format value "+args[i]);
+                                    printHelp();
+                                    System.exit(-1);
+                            }
+                        } else {
+                            System.err.println("Format value is not provided");
+                            printHelp();
+                            System.exit(-1);
+                        }
+                        break;
+                    case "-h" :
+                    case "-help" :
+                    case "-?" :
+                        printHelp();
+                        break;
+                    default:
+                        System.err.println("Unknown parameter "+arg);
+                        System.exit(-1);
+                }
+            } else {
+                jars.add(arg);
+            }
+        }
         ClassParser cp;
         try {
-            for (String arg : args) {
+            switch (format) {
+                case XML:
+                    outputStream.println("<?xml version=\"1.1\" encoding=\"UTF-8\"?>");
+                    outputStream.println("<root>");
+                    break;
+            }
+            for (String arg : jars) {
 
                 File f = new File(arg);
                 
@@ -68,13 +153,27 @@ public static void main(String[] args) {
                         continue;
 
                     cp = new ClassParser(arg,entry.getName());
-                    ClassVisitor visitor = new ClassVisitor(cp.parse());
+                    ClassVisitor visitor = new ClassVisitor(cp.parse(),outputStream,format);
                     visitor.start();
                 }
             }
+            switch (format) {
+                case XML:
+                    outputStream.println("</root>");
+                    break;
+            }
         } catch (IOException e) {
             System.err.println("Error while processing jar: " + e.getMessage());
             e.printStackTrace();
         }
     }
+
+    private static void printHelp() {
+        System.out.println("Constructs a callgraph out of a JAR archive. Can combine multiple archives into a single call graph");
+        System.out.println("See https://github.com/gousiosg/java-callgraph for more details");
+        System.out.println("Options:");
+        System.out.println("-h, -help, -? This help message");
+        System.out.println("-f, -format Set output format. Possible values 'xml' or 'txt' (default)");
+        System.out.println("-o, -out File for output. Default - to console");
+    }
 }
diff --git a/src/main/java/gr/gousiosg/javacg/stat/MethodVisitor.java b/src/main/java/gr/gousiosg/javacg/stat/MethodVisitor.java
index 4dd0821b..9280414c 100644
--- a/src/main/java/gr/gousiosg/javacg/stat/MethodVisitor.java
+++ b/src/main/java/gr/gousiosg/javacg/stat/MethodVisitor.java
@@ -31,6 +31,8 @@
 import org.apache.bcel.classfile.JavaClass;
 import org.apache.bcel.generic.*;
 
+import java.io.PrintStream;
+
 /**
  * The simplest of method visitors, prints any invoked method
  * signature for all method invocations.
@@ -43,22 +45,47 @@ public class MethodVisitor extends EmptyVisitor {
     private MethodGen mg;
     private ConstantPoolGen cp;
     private String format;
+    private PrintStream output;
+    private FormatEnumaration outputFormat;
 
-    public MethodVisitor(MethodGen m, JavaClass jc) {
+    public MethodVisitor(MethodGen m, JavaClass jc, PrintStream output, FormatEnumaration format) {
         visitedClass = jc;
         mg = m;
         cp = mg.getConstantPool();
-        format = "M:" + visitedClass.getClassName() + ":" + mg.getName() + "(" + argumentList(mg.getArgumentTypes()) + ")"
-            + " " + "(%s)%s:%s(%s)";
+        this.outputFormat = format;
+        this.output = output;
+        switch (outputFormat) {
+        case TXT:
+            this.format = "M:" + visitedClass.getClassName() + ":" + mg.getName() + "(" + argumentList(mg.getArgumentTypes(),false) + ")"
+                    + " " + "(%s)%s:%s(%s)";
+            break;
+        case XML:
+            this.format = "<invoke type=\"%s\" reference=\"%s\" call=\"%s\" signature=\"%s\"/>";
+            break;
+        default:
+            throw new RuntimeException("Unsupported format "+outputFormat);
+        }
     }
 
-    private String argumentList(Type[] arguments) {
+    private String argumentList(Type[] arguments,boolean flat) {
         StringBuilder sb = new StringBuilder();
         for (int i = 0; i < arguments.length; i++) {
-            if (i != 0) {
-                sb.append(",");
+            if (flat || outputFormat==FormatEnumaration.TXT) {
+                if (i != 0) {
+                    sb.append(",");
+                }
+                sb.append(arguments[i].toString());
+            } else {
+                switch (outputFormat) {
+                    case XML:
+                        sb.append("<arg>");
+                        sb.append(arguments[i].getSignature());
+                        sb.append("</arg>");
+                        break;
+                    default:
+                        throw new RuntimeException("Unsupported format "+outputFormat);
+                }
             }
-            sb.append(arguments[i].toString());
         }
         return sb.toString();
     }
@@ -66,13 +93,35 @@ private String argumentList(Type[] arguments) {
     public void start() {
         if (mg.isAbstract() || mg.isNative())
             return;
-        for (InstructionHandle ih = mg.getInstructionList().getStart(); 
+        switch (outputFormat) {
+            case XML:
+                output.print("<method name=\""+ClassVisitor.xmlEscapeText(mg.getName())+"\" signature=\"");
+                output.print(argumentList(mg.getArgumentTypes(),true));
+                output.println("\">");
+                break;
+        }
+        for (InstructionHandle ih = mg.getInstructionList().getStart();
                 ih != null; ih = ih.getNext()) {
             Instruction i = ih.getInstruction();
-            
+//            if (outputFormat== FormatEnumaration.XML && i instanceof ConstantPushInstruction) {
+//                ConstantPushInstruction pushInstruction = (ConstantPushInstruction)i;
+//                output.println("<ConstantPushInstruction>");
+//                output.println(pushInstruction.getValue());
+//                output.println("</ConstantPushInstruction>");
+//            }
             if (!visitInstruction(i))
                 i.accept(this);
         }
+        switch (outputFormat) {
+            case XML:
+                output.println("</method>");
+                break;
+        }
+    }
+
+    @Override
+    public void visitLCONST(LCONST obj) {
+        super.visitLCONST(obj);
     }
 
     private boolean visitInstruction(Instruction i) {
@@ -82,29 +131,38 @@ private boolean visitInstruction(Instruction i) {
                 && !(i instanceof ReturnInstruction));
     }
 
+//    @Override
+//    public void visitLocalVariableInstruction(LocalVariableInstruction obj) {
+//        switch (outputFormat) {
+//            case XML:
+//                output.println("<local name=\""+obj.getName()+"\">"+obj.toString(true)+"</local>");
+//                break;
+//        }
+//    }
+
     @Override
     public void visitINVOKEVIRTUAL(INVOKEVIRTUAL i) {
-        System.out.println(String.format(format,"M",i.getReferenceType(cp),i.getMethodName(cp),argumentList(i.getArgumentTypes(cp))));
+        output.println(String.format(format,"M",i.getReferenceType(cp), ClassVisitor.xmlEscapeText(i.getMethodName(cp)),argumentList(i.getArgumentTypes(cp),true)));
     }
 
     @Override
     public void visitINVOKEINTERFACE(INVOKEINTERFACE i) {
-        System.out.println(String.format(format,"I",i.getReferenceType(cp),i.getMethodName(cp),argumentList(i.getArgumentTypes(cp))));
+        output.println(String.format(format,"I",i.getReferenceType(cp),ClassVisitor.xmlEscapeText(i.getMethodName(cp)),argumentList(i.getArgumentTypes(cp),true)));
     }
 
     @Override
     public void visitINVOKESPECIAL(INVOKESPECIAL i) {
-        System.out.println(String.format(format,"O",i.getReferenceType(cp),i.getMethodName(cp),argumentList(i.getArgumentTypes(cp))));
+        output.println(String.format(format,"O",i.getReferenceType(cp),ClassVisitor.xmlEscapeText(i.getMethodName(cp)),argumentList(i.getArgumentTypes(cp),true)));
     }
 
     @Override
     public void visitINVOKESTATIC(INVOKESTATIC i) {
-        System.out.println(String.format(format,"S",i.getReferenceType(cp),i.getMethodName(cp),argumentList(i.getArgumentTypes(cp))));
+        output.println(String.format(format,"S",i.getReferenceType(cp),ClassVisitor.xmlEscapeText(i.getMethodName(cp)),argumentList(i.getArgumentTypes(cp),true)));
     }
 
     @Override
     public void visitINVOKEDYNAMIC(INVOKEDYNAMIC i) {
-        System.out.println(String.format(format,"D",i.getType(cp),i.getMethodName(cp),
-                argumentList(i.getArgumentTypes(cp))));
+        output.println(String.format(format,"D",i.getType(cp),ClassVisitor.xmlEscapeText(i.getMethodName(cp)),
+                argumentList(i.getArgumentTypes(cp),true)));
     }
 }