Here are some useful download sites for Java developers. I’ve generally chosen the open source and/or free download version of tools as these are the ones I use most of the time.
The master copy of this page is at https://darwinsys.com/java/downloads.html
Note: W M L means Windows, Mac and Linux downloads. Default (or J) is pure-Java download. Some offer both!
Java runtime (for running applications and/or for running in the browser) W M L https://www.java.com
OpenJDK download: W M L http://jdk.java.net/
Oracle JDK: W M L https://www.oracle.com/technetwork/java/javase/downloads/ Licensing issues may apply!
OpenBSD/NetBSD/FreeBSD: in your system’s ports/packages tree:
# pkg_add -vU jdk-11 # e.g., on OpenBSD
Java Build Tools
For new projects you should probably use Maven as your build tool: https://maven.apache.org/ (download links for binary and source)
Or maybe Gradle https://gradle.org
The oldest build tool, ant, is still available at https://ant.apache.org (download links for binary and source), but its use is in decline due to its extremely verbose build files; it’s been called "the assembly language of build tools".
Integrated Development Environments
The "big 3" Java IDEs all have plug-in support for lots of languages and formats. My personal favorite is Eclipse, but for Android work I have to use Android Studio, built on IntelliJ.
Eclipse Download: W M L https://www.eclipse.org/downloads/
IntelliJ IDea Download: https://www.jetbrains.com/idea/download/
NetBeans Download: https://netbeans.org/downloads/
Java EE App Server
WildFly https://wildfly.org/downloads/ WildFly is the project once known as "JBoss Application Server".
TomEE https://tomee.apache.org/ TomEE (pronounced like "Tommy") is the standard Apache Tomcat Java-powered web server, with JAR files already added into it to make it a full Java EE server.
GlassFish Download https://glassfish.java.net/download.html
Web Services Code
Jersey examples: https://github.com/jersey/jersey/tree/master/examples
SoapUI download W M L https://www.soapui.org/downloads/latest-release.html
https://github.com/IanDarwin/javasrc (and other repos there) - General Java examples.