How to get the value of an Annotation type Element ?

package com.test;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

public class ValueAnnotation {

    protected @interface  TypeUse {
        int value();

    @TypeUse(value = 0) class Test<T>{



    private void processEnclosedElements(List<? extends Element> enclosedElements,
                                         RoundEnvironment roundEnv) {

        for( Element e : enclosedElements ){

            if (e.getKind() == ElementKind.CLASS){

                System.out.println( "Annotation [" + e.getAnnotationMirrors() + "] [" + e  + "]");


    private void processClassTypeParameters(Element e) {

            for( AnnotationMirror am  : e.getAnnotationMirrors() ){

                for(Map.Entry< ? extends ExecutableElement, ? extends AnnotationValue> m : am.getElementValues().entrySet()){

                    System.out.println( "[" + m.getKey() +"][" + m.getValue() + "]");



Annotation [@com.test.ValueAnnotation.TypeUse(0)] [com.test.ValueAnnotation.Test]


I came across this code that uses a cast to assign a Lambda expression to a marker interface in Angelika Langer’s explanation.

Serializable f2
= (BiPredicate<String,String> & Serializable)
(s,t) -> s.equalsIgnoreCase(t);

As I was curious about this I tried to detect an intersection type (T extends String & @IntersectionType.TypeUse(value = 2) Serializable) and print the annotation applied on one of its bounds.

The result is

Annotation [] [com.test.IntersectionType.Test]
Annotation [[]] [java.lang.String]
Annotation [[]] []

This could be a JDK 8 bug at this time. I am getting nothing.

I am using

java version "1.8.0-ea"
Java(TM) SE Runtime Environment (build 1.8.0-ea-b123)
Java HotSpot(TM) 64-Bit Server VM (build 25.0-b65, mixed mode)

I presumed there is a javax.lang.model.type.IntersectionType that will match T extends String & Serializable. So I though there is a TypeMirror that I can check for that type. But it does not seem so.

I will update later when I get a proper result.

Update : The method is updated and it works partly. I am getting the intersection type. But I think one cannot get the annotation type of the intersection type directly because the annotation is applied on each of the bounds separately. So the old code(see the comments below) is sufficient but now the returned array is empty which could mean that this is a bug in itself.

Annotation [] [com.test.IntersectionType.Test]
Annotation [[]] [java.lang.String&]
Annotation [[]] [java.lang.String]
Annotation [[]] []

public class IntersectionType {

    public @interface TypeUses {
        TypeUse[] value();

    protected @interface  TypeUse {
        int value();

    //Intersection type
    class Test<T extends String & @IntersectionType.TypeUse(value = 2) Serializable>{


Processor method

    private void processClassTypeParameters(Element e) {

        for (TypeParameterElement typeParameterElement : ((TypeElement) e).getTypeParameters()) {

            for( AnnotationMirror am  : typeParameterElement.getAnnotationMirrors() ){

                System.out.println( "Annotation [" + am + "] [" + typeParameterElement  + "]");

            //Get the intersection type
            TypeVariable tv = (TypeVariable)typeParameterElement.asType();

            TypeMirror tm = tv.getUpperBound();
            //This may not return anything.(See explanation above)
            System.out.println( "Annotation [" + Arrays.asList( tm.getAnnotationsByType(com.test.IntersectionType.TypeUse.class)) + "] [" + tm  + "]");

            for (TypeMirror typeMirror : typeParameterElement.getBounds()) {
                //Commented section is not the right way
                //if( typeMirror instanceof javax.lang.model.type.IntersectionType) {

                //The following line returns an empty array most probably due to a different bug.
                    System.out.println( "Annotation [" + Arrays.asList(typeMirror.getAnnotationsByType(com.test.IntersectionType.TypeUse.class)) + "] [" + typeMirror  + "]");


Garbage collection book


I have started reading this but there is no plan to complete it at this time. I will try.

I will try to write about key research topics in the book if I understand it well. I know that is hard for a run-of-the-mill software developer like me.

In fact I started reading the earlier version more than 5 years back but never completed it.

Porting Python BoxPlot code to “R”

My previous two entries explained how I am attempting to port the Python code used to create the graph in the DZone article to “R”.

The author of that article published the data that he used to generate the graph. The data consists of several files. I have taken one file and tried to create boxplots from it. I will improve this by combining all the files, parsing them and generating a combined boxplot. But first I coded this “R” script to parse one file and generate a boxplot.

The data from one of the files looks like this.

1346999466187,32,Home page - anon,200,OK,Anonymous Browsing 1-2,text,true,31
1346999466182,37,Login form,200,OK,Node save 3-1,text,true,36
1346999466184,35,Home page - anon,200,OK,Anonymous Browsing 1-11,text,true,32
1346999466182,37,Home page - anon,200,OK,Anonymous Browsing 1-1,text,true,34
1346999466189,30,Home page - anon,200,OK,Anonymous Browsing 1-4,text,true,27
1346999466185,46,Home page - anon,200,OK,Anonymous Browsing 1-5,text,true,34
1346999466185,44,Search,200,OK,Search 4-1,text,true,35
1346999466188,28,Home page - anon,200,OK,Anonymous Browsing 1-3,text,true,26
1346999466182,33,Home page - anon,200,OK,Anonymous Browsing 1-7,text,true,32
1346999466182,36,Login Form,200,OK,Perform Login/View Account 5-1,text,true,35
1346999466182,35,Home page - anon,200,OK,Anonymous Browsing 1-10,text,true,33
1346999466182,34,Login Form,200,OK,Authenticated Browsing 2-1,text,true,32
1346999466184,33,Home page - anon,200,OK,Anonymous Browsing 1-6,text,true,31
1346999466182,37,Home page - anon,200,OK,Anonymous Browsing 1-9,text,true,35

It is very easy to parse this and create a “R” data frame.

# TODO: Box Plots
# Author: radhakrishnan


options("scipen"=100, "digits"=4)

data <- read.table("~/Documents/Learn R Statistics/R/jmeter_results/4-overall-summary.csv",sep=",",header=T)


#I don't think I need 'ddply' here but it serves the purpose.
#It groups the data based on the 'label' and returns the two relevant columns
data <- ddply( data , .variables = "label" , .fun = function(x) x[,c("label","elapsed")])

uniquelables <- as.character(unique(data$label))
lists <- replicate( length(uniquelables),list())

j = 1

for (i in uniquelables ){
  lists[j] = as.list([data$label %in% i,'elapsed']))
  j = j + 1


BoxPlot from one file


Eclipse StatET-R environment

My Eclipse R environment is ready.

Screen Shot 2014-01-08 at 1.05.46 PM



I wanted to generate the boxplot graphs in this DZone article using ‘R’. I think this is one of the best graphs I have seen. It shows data in a really useful manner that could help our Capacity Planners. I am quite proficient with basic ‘R’ data analysis and plots.

So I started to look at matplotlib,a powerful Python plotting library. So as a first step I coded this Python program using matplotlib.

  1. I am using PyDev plugin for eclipse.
  2. I am also using Enthought Canopy as by Python interpreter. This package has all the libraries I need.

    I strugged for some time to configure the Python packages so that Pydev can use them properly instead of the default Python in my Mac machine.

    All is well in the end. I have coded Python in the past but my skills are rudimentary but still this code was simple. It has many similarities to ‘R’.

    import numpy as np
    import matplotlib
    import matplotlib.pyplot as plt
    x = []
    y = []
    data = [[ 6.2, 18, 0.3444444  ],
            [ 1.0,  11, 0.3636364 ],
            [ 2.0,  11, 0.3636364 ],
            [ 3.3,  9, 0.3666667  ],
            [ 4.2,  12, 0.3500000 ],
            [ 3.2,  12, 0.3500000 ],
            [ 5.2,  12, 0.3500000 ],
            [ 6.3,  12, 0.3500000 ],
            [ 7.2,  12, 0.3500000]]
    for list in data:
        for number in list[:1]:
    for list in data:
        for number in list[2:3]:
    plt.xlim( (0, 8) )