Core Java APIs and programming techniques
Technologies related to Java APIs (application programming interfaces) and JDK (Java Development Kit) form the cornerstone of modern, enterprise-grade software development. Here we explore all the Java features that make the JVM great through programming tutorials, real-world code samples and expert opinions from Java champions.
Top Stories
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Video
20 Nov 2024
OpenAPI, Swagger and Python
Looking for an easy way to create, test and document your RESTful APIs written in Python? Swagger and OpenAPI make it easy. This tutorial shows you how to do it. Continue Reading
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Tip
19 Nov 2024
Top 10 Jenkins alternatives
Tired of the overhead of hosting your own Jenkins installation and looking for some alternatives? Here are 10 of the best. Continue Reading
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Tip
21 Jul 2023
The dangers of Python import and how enterprises can be safe
The Python import statement carries a security risk that developers and enterprises need to watch out for. Here's how it works and why there's no easy fix. Continue Reading
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Blog Post
19 Jul 2023
Sprint vs Scrum: What's the difference?
The comparison of Scrum versus a sprint is less about differences and more about how Agile frameworks such as Scrum, SAFe and XP use short development cycles to limit risk and keep stakeholders ... Continue Reading
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Blog Post
13 Jul 2023
How to enable Java 21 preview features
Java 21 includes numerous highly anticipated preview features including String templates, scoped variables and unnamed classes. Here's how to enable Java 21 preview features on your JDK. Continue Reading
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Definition
13 Jul 2023
Remote Method Invocation (RMI)
Remote Method Invocation (RMI) is an application programming interface (API) in the Java programming language and development environment. Continue Reading
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Tutorial
12 Jul 2023
Understanding the TypeScript method decorator
This tutorial explores TypeScript method decorators, reusable code similar to Java annotations that lets developers apply logic in a declarative manner at design time. Continue Reading
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Definition
10 Jul 2023
Java Mission Control
Java Mission Control is a performance-analysis tool that renders sampled JVM metrics in easy-to-understand graphs, tables, histograms, lists and charts. Continue Reading
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Blog Post
10 Jul 2023
Scrum's chicken and pigs parable
In a ham and eggs breakfast, the chicken is involved, but the pig's 100% committed. That's the problematic basis of Scrum's chicken and pigs parable. Continue Reading
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Definition
10 Jul 2023
snake case
Snake case is a naming convention where a developer replaces spaces between words with an underscore. Continue Reading
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Blog Post
03 Jul 2023
Create your first Java AWS Lambda function in minutes
If you haven't created a Java-based AWS Lambda function before, you'll be amazed at how easy it is. This quick AWS, Lambda and Java tutorial will quickly get you started in the world of serverless ... Continue Reading
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Blog Post
01 Jul 2023
The var keyword in Java
While the use of var in Java brings inferred typing to the platform, it does not negate Java's dedication to strong typing. Here's how the Java var keyword works, along with simple examples of how ... Continue Reading
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Tip
30 Jun 2023
How to apply the open-closed principle in Java
How does the open-closed SOLID principle work in a Java program? Here we show you what this important principle means, and how to implement the open-closed principle in Java. Continue Reading
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Definition
27 Jun 2023
pseudocode
Pseudocode is a detailed yet readable description of what a computer program or algorithm should do. Continue Reading
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Quiz
20 Jun 2023
10 WebAssembly questions to test your Wasm knowledge
Test your knowledge of WebAssembly with this tough, ten-question quiz on the benefits and applications of the new Wasm standard. Continue Reading
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Definition
19 Jun 2023
requirements analysis (requirements engineering)
Requirements analysis (requirements engineering) is the process of determining user expectations for a new or modified product. Continue Reading
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Definition
12 Jun 2023
lambda
Lambda, the 11th letter of the Greek alphabet, is used as both a symbol and a concept in various fields of science, mathematics and computing. Continue Reading
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Blog Post
06 Jun 2023
How Java instance main methods and unnamed classes work
Say goodbye to the public static void main method in Java 21 with the unnamed classes and instance main methods preview features. Continue Reading
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Blog Post
04 Jun 2023
Hibernate and JPA column mapping with annotations
Effective Hibernate and JPA column mapping requires the use of the @Column annotation to set important properties such as nullability, uniqueness, precision and scale. Continue Reading
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Blog Post
01 Jun 2023
How System.out in Java works
New developers are often confused by the line of System.out.println() code they write when first introduced to Java. Here's a quick explanation of what System.out.println() means. Continue Reading
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Blog Post
01 Jun 2023
How to use native SQL in Hibernate and JPA
Need to use raw SQL with JPA and JPA? The Jakarta Persistence API's NativeQuery interface makes it possible to use Hibernate, SQL and JPA together in the same app. Continue Reading
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Blog Post
31 May 2023
Java's print vs println method: What's the difference?
What's the difference between print and println methods in Java? Our examples show that it comes down to the fact that println adds a newline character to output, while Java's print method does not. Continue Reading
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Definition
31 May 2023
tuple
A tuple, pronounced TUH-pul, is an ordered and finite list of elements in various fields of interest, including computing. Continue Reading
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Definition
22 May 2023
API security
Application program interface (API) security refers to policies and procedures that protect APIs against malicious attacks and vulnerabilities. Continue Reading
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Definition
19 May 2023
no op (no operation)
No op means 'no operation,' which is a computer instruction that specifies no operation but takes up a small amount of storage space. Continue Reading
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Definition
16 May 2023
Unicode
Unicode is a universal character encoding standard that is maintained by the Unicode Consortium, a standards organization founded in 1991 for the internationalization of software and services. Continue Reading
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Blog Post
15 May 2023
Hibernate and JPA 3 CRUD example
Struggling to get your first JPA 3 application off the ground? Here's a quick Hibernate and JPA 3 CRUD example to help you get going with the latest version of the Java Persistence API. Continue Reading
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Tip
09 May 2023
How to address Python performance problems
Python is a great language for nonprogrammers to do mathematical and scientific tasks, even if such optimization impacts performance. Here's why that's not a fair criticism. Continue Reading
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Blog Post
01 May 2023
The right MySQL persistence.xml example file for JPA 3 and Hibernate 6
A quick migration from JPA 2.x to 3.x can become bottlenecked if the persistence.xml file is misconfigured. Here's what a proper persistence.xml file for JPA 3, Hibernate 6 and a MySQL database ... Continue Reading
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Blog Post
30 Apr 2023
How to write your first Java program
Want to learn to code and write your first Java program? Here's a quick and fun Java programming tutorial that will have your running your first Java program in less than 10 minutes. Continue Reading
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Blog Post
25 Apr 2023
Hello World in Python vs Java
'Hello World' is a silly criterion to use when comparing programming languages. Yet here we are, comparing 'Hello World' in Java vs Python. We'll let you judge the winner. Continue Reading
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Tip
31 Mar 2023
JavaScript vs. TypeScript: What's the difference?
TypeScript and JavaScript are two complementary technologies that are driving both front-end and back-end development. Here are the similarities and differences between the two. Continue Reading
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Tip
30 Mar 2023
How to apply the single responsibility principle in Java
How does the single responsibility model work in a Java program? Here we show you what this SOLID principle means, and how to implement the single responsibility model in Java. Continue Reading
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Blog Post
29 Mar 2023
Why is the Bootstrap grid system 12 columns wide?
Ever wonder why they created a 12-column Bootstrap grid system, and not 10 or 15? It's the same reason there's 60 seconds in a minute, or 360 degrees in a circle. Continue Reading
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Blog Post
28 Mar 2023
There's a new Java build system named Bld
Want to write your software build logic entirely in Java? A new build tool called Bld does exactly that, and Geert Bevin and Erik Thauvin are behind it. Continue Reading
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Definition
28 Mar 2023
object-relational mapping (ORM)
Object-relational mapping (ORM) is a way to align programming code with database structures. Continue Reading
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Blog Post
19 Mar 2023
Critical Java JVM options and parameters
The easiest way to optimize your Java runtime is to supply correct JVM options and parameters. In honor of the Java 21 release, we examine the 21 most important Java JVM options you can configure. Continue Reading
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Blog Post
04 Mar 2023
Real world Java applications
Java runs on billions of devices, and Java applications of importance run on systems all over the world. Here are the top 10 applications of Java technology today, plus a look at what the future ... Continue Reading
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Blog Post
28 Feb 2023
Top 10 software myths debunked
Software myths abound in the IT industry. Here are the top 10 software devlepment myths and misconceptions, along with a full debunking of these mythical ideas. Continue Reading
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Blog Post
26 Feb 2023
How to use JShell in Java
If you haven't used Java's JShell yet, you're missing out. Here's a quick Java and JShell tutorial to get you started. Continue Reading
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Definition
22 Feb 2023
abstract class
An abstract class is a template definition of methods and variables in a specific class, or category of objects. Continue Reading
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Tip
15 Feb 2023
Why Java in 2023?
Has there ever been a better time to be a Java programmer? From new Spring releases to active JUGs, the Java platform is experiencing a renaissance. Continue Reading
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Tip
27 Jan 2023
How developers can avoid remote work scams
Software developers can find good remote programming jobs, but some job offers are too good to be true. Follow these tips to spot remote job scams. Continue Reading
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Tip
12 Jan 2023
Tips and tricks for TypeScript programming
For those new to TypeScript or for Java developers transitioning into JavaScript, these three TypeScript tips and tricks modern day software developers will come in handy. Continue Reading
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Tutorial
06 Jan 2023
11 lessons learned from writing my first Java program
You'll be amazed how easy it is to learn Java and write powerful cross-platform applications when writing your first Java program. Some misconceptions about Java just aren't true. Continue Reading
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Blog Post
04 Dec 2022
How do you say Udemy? The 11 most mispronounced tech terms
How do you say Udemy? How do you pronounce JSON or GIF? There's a right way and there's a wrong way. Learn the right way to say these commonly mispronounced tech terms. Continue Reading
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Tip
25 Oct 2022
The differences between Java and TypeScript devs must know
Do you know Java? Are you trying to learn TypeScript? Here are five differences between TypeScript and Java that will make the learning transition easier. Continue Reading
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Tutorial
29 Sep 2022
Your top 4 Java user input strategies
From System.in to the Scanner class, there are many ways to read user input into your Java programs. Find out which Java user input strategy is best for your software needs. Continue Reading
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Tutorial
29 Sep 2022
How Java's System.in reads input from the user
The Java System.in component provides universal access to console-based user input. Learn how to make your applications interactive with this Java System.in tutorial. Continue Reading
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Blog Post
09 Sep 2022
Java Exception handling best practices
Don't let the complexities of Java Exception handling get you down. Follow these top 10 Java Exception handling examples and you'll be an expert in handling errors in your Java code. Continue Reading
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Definition
26 Aug 2022
Java string
A Java string is a sequence of characters that exists as an object of the class java.lang. Continue Reading
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Blog Post
24 Jul 2022
How to format a Java String with printf example
The Java String printf method makes adding and formatting text incredibly easy. In this quick tutorial, you'll learn by example how to format, justify, pad and case output printed with Java's ... Continue Reading
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Blog Post
18 Jul 2022
How to format a Java int or long with printf example
Here's a quick tutorial on how to use printf to format Java int, long, short and byte values. It's pretty easy to do. And the output you can generate can be very visually appealing. Continue Reading
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Blog Post
17 Jul 2022
How to format a Java table with printf example
Why not make your console output look pretty? Create, format and print data tables with Java printf statements, along with a clever combination of dashes, pipelines and printf placeholders. Continue Reading
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Blog Post
11 Jun 2022
Example Java String palindrome checker program using recursion
There are many ways to write a Java String palindrome program. In this Java palindrome example we demonstrate recursion and how the use of loops, arrays, Scanner and the reverse method can improve ... Continue Reading
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Blog Post
09 Jun 2022
Java length vs length(): What's the difference?
Have you ever been confused between length and length() in Java? Here we show you the difference between Java length properties and methods, and when to use them in your code. Continue Reading
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Blog Post
20 Apr 2022
CDI Full vs CDI Lite: What's new in Contexts and Dependency Injection 4.0
There's an interesting change packaged inside the CDI 4.0 release that will change the way you think about the API. Version 4.0 of Jakarta Contexts and Dependency Injection (CDI) changed the ... Continue Reading
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Tip
13 Apr 2022
Either log or rethrow Java exceptions, but never do both
When an exception occurs in your Java code, you can log it or you can rethrow it -- but don't do both. Here's why you must avoid that exception handling antipattern. Continue Reading
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Tip
01 Apr 2022
7 tips to choose the right Java library
Your application is only as secure and reliable as the external libraries you use. Here's a list of the top 7 things to consider when choosing a software library for your project. Continue Reading
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Tutorial
30 Mar 2022
An example of how suppressed exceptions in Java work
Don't ignore suppressed exceptions. In this quick tutorial we show you how to anticipate when code will throw suppressed exceptions, along with the best practices to handle them. Continue Reading
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Tutorial
30 Mar 2022
A simple 'try with resources' in Java example
Java's 'try-with-resources' exception handling feature can help you write better, more effective Java code. Here's a quick example of the try with resources construct in action. Continue Reading
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Quiz
21 Mar 2022
A tough, multiple choice Java exception handling quiz
Just how well do you know exception handling in Java? These 10 tough multiple-choice questions on checked and unchecked exceptions will test your error handling mettle. Continue Reading
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Tip
16 Mar 2022
Fix these 10 common examples of the RuntimeException in Java
Don't let the occurrence of a RuntimeException in Java bring your code to a standstill. Here are 10 examples of how to avoid runtime exceptions in Java. Continue Reading
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Tip
08 Mar 2022
Fix the 5 most common types of runtime errors in Java
The key to bug-free code is an awareness of the most common types of runtime errors in Java, along with the knowledge of how to avoid them. Continue Reading
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Tutorial
11 Feb 2022
Fix the top 10 most common compile time errors in Java
Flummoxed why your Java code won't compile? Here are the 10 most commonly encountered Java compile errors, along with the fixes that will get your code working in no time. Continue Reading
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Opinion
01 Feb 2022
5 tech trends that foretell the future of Java in 2022
Here's what 2022 has in store for developers, programmers and DevOps professionals who work in the server-side Java space. Continue Reading
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Definition
25 Jan 2022
AJAX (Asynchronous JavaScript and XML)
AJAX (Asynchronous JavaScript and XML) is a technique aimed at creating better and faster interactive web apps by combining several programming tools including JavaScript, dynamic HTML (DHTML) and Extensible Markup Language (XML). Continue Reading
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Tip
10 Jan 2022
Binary and hexadecimal numbers explained for developers
For developers who are intimidated by bit shifts and hex operation, here's a thorough explanation of how binary and hexadecimal number systems work. Continue Reading
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Blog Post
31 Dec 2021
The psychology of offering developers programming advice
Need to provide programming advice, or perhaps even harsh criticisms to a team of developers? Here's a nice way, pyscyhologically sound, way to do it. Continue Reading
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Tip
06 Dec 2021
Problems with Java modules still plague developers
The Java Platform Module System promised to fix the missteps of the past. Unfortunately, it has repeated the problems that plagued OSGi and JBoss Modules. Continue Reading
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Tip
18 Nov 2021
Iterator vs. ListIterator: Which interface should you choose?
When the need exists to manipulate an ordered collection, the Java Iterator runs out of steam. Learn how Java's ListIterator improves upon the more generic Iterator interface. Continue Reading
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Tip
14 Oct 2021
5 best Java 17 features that developers will love
The new Java 17 release contains plenty of new features that will intrigue developers. Here are five features that should push developers off the Java 11 LTS to JDK 17. Continue Reading
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Definition
13 Oct 2021
Hibernate
Hibernate is an open source object relational mapping (ORM) tool that provides a framework to map object-oriented domain models to relational databases for web applications. Continue Reading
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Tip
30 Sep 2021
3 simple Java Hello World examples
Are you a developer who's new to Java? Here are three ways to write a Hello World program in Java on Eclipse and get started with the popular programming language. Continue Reading
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Blog Post
14 Sep 2021
Every change between JDK 11 and the Java 17 LTS release
Wondering what's included in the new Java 17 LTS release? Here's a list of all the changes made to the JDK between the Java 11 and Java 17 LTS releases. Continue Reading
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Guest Post
18 Aug 2021
The benefits and drawbacks of Java's fail-safe iterators
Iterators in Java are a simple mechanism to help developers avoid runtime exceptions. Let's explore the difference between fail-fast and fail-safe iterators. Continue Reading
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Answer
16 Jul 2021
Kebab vs. camel case: How these naming conventions differ
What is the difference between a variable written in kebab case vs. camel case? Here we'll show you how these naming conventions differ and when to use one over the other. Continue Reading
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Feature
25 Jun 2021
Java naming conventions, explained
You could start a Java variable with a dollar sign, but no one does. When you write Java code, always follow these standard Java naming conventions. Continue Reading
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Answer
23 Jun 2021
Why is Java platform-independent?
Sun Microsystems architects designed Java to be cross-platform. But why? Here we look at not only why Java works across platforms, but also how it achieves its platform independence. Continue Reading
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Blog Post
03 Jun 2021
Fix the ConcurrentModificationException
Has the ConcurrentModificationException been thrown in you Java app? Here are four simple ways to fix the ConcurrentModificationException in your code. Continue Reading
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Answer
30 Apr 2021
Camel case vs. snake case: What's the difference?
The use of white space is what separates camel case and snake case. Camel case has none, while snake case uses underscores. Let's review some examples to make this clear. Continue Reading
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Blog Post
30 Apr 2021
Yes, the original name for Java was Oak
When Sun Microsystems first developed a programming language to power their Star7 entertainment controller, they named it Oak, not Java. Continue Reading
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Quiz
29 Apr 2021
Test your knowledge of Java foundations
Whether you're new to Java or have worked with the language for years, you need to know the foundational building blocks. Review the basics in this Java quiz. Continue Reading
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Feature
27 Apr 2021
A guide to common variable naming conventions
Every developer should know the basic variable naming conventions to more easily move from language to language. Review the common ones here like Pascal, camel and snake case. Continue Reading
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Answer
23 Apr 2021
Kubernetes vs. Rancher: The differences all devs should know
How are Kubernetes and Rancher related? Here are the basics developers need to know about Kubernetes and Rancher and how they can ultimately work together. Continue Reading
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Answer
15 Apr 2021
Interpreted vs. compiled languages: What's the difference?
Learn the difference between compiled languages like Go and interpreted ones like Java. One language is platform agnostic. The other can run a bit faster. Continue Reading
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News
08 Apr 2021
Microsoft previews OpenJDK distro to the delight of devs
In a move meant to attract more Java developers to its Azure cloud and further support the Java community, Microsoft launched a preview of its own distribution of OpenJDK. Continue Reading
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News
06 Apr 2021
Supreme Court ruling on Java APIs eases developer worries
Now that the Supreme Court has ruled for Google over Oracle in their high-stakes copyright battle over Java APIs, developers can rest easier -- but some questions linger. Continue Reading
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Blog Post
30 Mar 2021
Recursion vs Iteration: What's the difference?
This Java recursion tutorial shows you how to create a recursive Java factorial function and compares these methods to iterative ones. Continue Reading
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Answer
26 Mar 2021
Pascal case vs. camel case: What's the difference?
It's easy to confuse camel case and Pascal case. We'll show you the difference between the two common variable naming conventions, along with some examples. Continue Reading
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News
25 Mar 2021
AdoptOpenJDK moves to Eclipse Foundation as Adoptium
The Eclipse Foundation has launched a new working group to provide governance, IP services and developer advocacy for Adoptium, the newly renamed AdoptOpenJDK distribution of the OpenJDK spec. Continue Reading
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Definition
24 Mar 2021
What is Pascal case?
Pascal case is a naming convention in which developers start each new word in a variable with an uppercase letter. Continue Reading
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News
16 Mar 2021
Oracle delivers Java 16 to developers
Oracle has released Java 16, the latest version of the Java Development Kit (JDK) for developers. The company also moved the OpenJDK source code repositories from Mercurial to Git. Continue Reading
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Answer
08 Mar 2021
How do microservices API gateways aid monolith migrations?
How do you move a set of REST resources to microservices? One way is to use an API gateway. Follow this example to learn how migrate to microservices-oriented architecture. Continue Reading
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News
03 Feb 2021
Oracle adds GraalVM Enterprise to Java SE subscription
Oracle's GraalVM Enterprise compiler technology is now available to developers as part of the Java SE subscription. GraalVM increases application performance. Continue Reading
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Definition
15 Jan 2021
What is Java Flight Recorder and how does it work?
Java Flight Recorder is a Java Virtual Machine (JVM) profiler that gathers performance metrics without placing a significant load on resources. Continue Reading
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Video
15 Jan 2021
5 ways to force Java garbage collection
A developer can't technically force garbage collection in Java, but it can be made a priority. If you need to free up heap space, here are five ways to prioritize it in the JVM. Continue Reading
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Feature
23 Dec 2020
What's in a name? What developers can expect in Jakarta EE 9
What Oracle called the Java EE API is now called Jakarta EE API under the Eclipse Foundation. Here's what developers can expect in the Jakarta EE 9 release. Continue Reading
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Quiz
15 Dec 2020
Test your knowledge of variable naming conventions
What's the difference between snake case and camel case? Or kebab case and pascal case? Try this 10-question variable naming quiz to learn more about programming variables. Continue Reading
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Definition
14 Dec 2020
What is Kebab case?
Kebab case -- or kebab-case -- is a programming variable naming convention where a developer replaces the spaces between words with a dash. Continue Reading
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Tutorial
18 Nov 2020
An Apache Commons FileUpload example and the HttpClient
In this article you will have a look at the capabilities of the HttpClient component and also some hands-on examples. Continue Reading
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Answer
05 Nov 2020
Why are curly braces in programming languages important?
Curly braces play a big role in code structure within popular programming languages such as Java, C++ and more. Here's how to properly line up code with curly brackets. Continue Reading