Category: Java

Sorting collections is a common task that Java developers deal with on a daily bases.  The Java Collections class provides us with two sort() methods to sort all collections that implement the List interface. Sorting Primitive Types & Strings In the example below, we will create a list with ten random integers and sort the list using the sort() method, […]Continue reading

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Iteration is the most common operations done on a collection. For example, you may want to go through all the student grades to find who has the highest test scores. In Java we have four methods for iterating over a collection, the methods are the for loop, iterator, forEach and lambda expressions. Setup Collection Here […]Continue reading

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Problem You are given a string and are asked to write a method to return true if the string is a palindrome and to return false otherwise. A palindrome is a string that reads the same from front to back like alula They are many solutions to check if a string is a palindrome. I’m going […]Continue reading

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What Is SDKMAN? As Java developers, we have to work with different versions of Java from project to project. Installing different versions by hand and setting the PATH can become a real pain at times. SDKMAN is a command line tool that allows you to install different versions of Java, Gradle, Maven and more. SDKMAN also takes […]Continue reading

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Apache Maven is distributed in several formats. The simplest way to install Maven is to download a ready-made binary distribution archive and follow the installation instructions. Maven 3.3+ release requires JDK 1.7 or above to execute. General Requirements Java JDK must be installed on system. Java 1.7 or higher is needed for Maven. To verify the […]Continue reading

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So your JUnit 5 tests are not running under Maven? You have JUnit 5 Tests which run fine from your IDE, but fail to run under Maven? Your test output looks like this:

The Cause The root cause is likely your Maven version. Maven 3.6.0 was released on October 24th, 2018. This release includes […]Continue reading

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It’s a fairly common task as a Java developer to convert from a List to an Array or from an Array to a list. In one of my previous post, I discussed about converting Map to List. Like many things in Java, there is often more than one way to accomplish a task. In this […]Continue reading

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In applications, you often need to work with a set of constant values. For example, representing a contract status with the “permanent”, “temp”, and “intern” values, or directions with the “north”, “south”, “east”, and “west” values. In Java, you use the enum type (short for enumeration), a special datatype introduced in Java 5 to represent […]Continue reading

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Converting a Java Map to a List is a very common task. Map and List are common data structures used in Java. A Map is a collection of key value pairs. While a  List is an ordered collection of objects in which duplicate values can be stored. In this post, I will discuss different ways to […]Continue reading

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A common requirement while programming in Java is to convert String to int. UI inputs in Web-based HTML, JSP, or Thymeleaf templates are transferred to backend Java applications as strings. It is the application developer’s responsibility to perform any String to int conversions to fulfil business logic, such as calculating discounts, storing age, and so […]Continue reading

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