Time based uuid generator in java (JUG library / example)
Generate time based uuid in java using JUG (Java Uuid Generator) library. JUG library provides couple of generator viz TimeBasedGenerator & RandomBasedGenerator. In […]
Core Java
IP Address from hostname (loopback, local & standard hosts) in java (example)
Given hostname in java, we would like to find out network details of host. JDK class InetAddress provide APIs to
List or display contents of compressed or zipped file in java (example)
Given a zipped or compressed file in java. We would like to display or list the contents of zipped file.
Compress or zip directory recursively in java (example)
Given an input directory containing files and sub-directories. We would like to compress or zip all files present in a
Create compress /zip file in java (ZipOutputStream class /example)
Given the input files in java, create zip or compress files using ZipOutputStream class . Java framework has provided couple of
Write or redirect standard output error stream to a file in java
Given a standard error output stream, Write the standard error to a file in java. We will use System.setErr method to redirect std output to a file.
Write or redirect console output to a file & again reset to standard output in java
In java application, we write to console output using System.out.print*. We would like to redirect console output to a file.
Convert String variable to Integer in java (example)
Given an String variable in java, we would like convert String to integer using Integer.parseInt, Integer.valueOf or Integer constructor (with example)
List multiple image, video, text files (extensions) in directory/folder (FilenameFilter/java)
Given input directory containing different files like image, video, text, csv, json etc. We would like to list files having
Recursively list all files present in directory /sub-directories of input folder (java /example)
Given an input directory of given file system in java. We would like to list all files present in a
List all directories of input path – scope operator & file filter in java
Given an input directory, List or print folders contained in a input directory path scope operator & file filter in java (IO operation /example)
Recursively list all files & folders of input directory in java (example)
Given an input directory or folder, we would like to list all files & folders in a directory. We will
Read property file from resource folder /directory in java (example)
Given a property file defining the properties of a java application. Property file will be residing in the resource folder/directory.
Java Concurrency – Thread join example with Runnable interface a
What thread’s join method? The join method allows one thread to wait for the completion of another thread. Suppose we
Print / list all fonts & font family using java (example)
List all system fonts and font families using GraphicsEnvironment. We will iterate through system fonts and we will print the
Calculate total, free & used memory of JVM heap store – Java runtime (example)
Given a java program, where we are allocating memory in heap store. We will allocate array (array of long primitives).
Print or list all environment variables using java8 streams
We will get list of all environment variables using System class. We will iterate through the map of system variables
Print or List locales, country codes / names / languages using java8
In current post, we will print /displays locales, country codes, country names and country languages. We will use Locale class
Print or list all system properties using java8 streams
Print or list or display all system properties using forEach method java 8 streams lambda. Print key value pairs of properties in java
Convert given string to character array in java (with example)
Given an input string in java, convert input string to character array. We will iterate through char array to print each character.
Difference b/w length & capacity method (impact of trim) of StringBuffer in java
StringBuffer is a thread-safe, mutable sequence of characters. StringBuffer can be modified at any point of time. We will look
Convert String object to lower case & upper case in java (example)
Given a String in java, we would like to convert the input String to lower case & upper case. String
Difference between == operator & equals method in java (example)
Difference between equality operator & equals method in java. == operator is used to compare primitives & equals method is used to compare objects (example)
Convert decimal number to binary – (java api, iterative & recursive)
Given a decimal number (base 10), convert decimal integer to binary number (base 2) using java. We will discuss various
Convert hexadecimal to decimal – java api, iterative & recursive
Given a hexadecimal number, convert hexadecimal number to decimal number using java. We will discuss various methods to convert hexadecimal
Convert decimal to hexadecimal – java api, iterative & recursive
Given a decimal number (base 10), convert decimal to hexadecimal number (base 16) using java. We will discuss various methods to
Find LCM of two numbers using GCD in java (example)
LCM (Least common multiple) of two integers is the least positive integer that is divisible by both a and b. e.g
Reverse each word of a string using StringBuilder in java (example)
Given a string in java, reverse each word of string using StringBuilder in java. Let us look into couple of
Reverse string word by word in java (stack/ stringbuilder /example)
Given a string in java, reverse the string word by word. Let us look into couple of examples to understand
Swap two numbers in java using third or temporary variable (example)
Given two input numbers, swap numbers using temporary variable. e.g. Given two input numbers x = 10 & y =