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 is pure-Java download. Some offer both!
JDK and Build Tools
Oracle JDK: W M L http://www.oracle.com/technetwork/java/javase/downloads/
For new projects you should probably use Maven as your build tool: http://maven.apache.org/ (download links for binary and source)
Or maybe Gradle.
The oldest build tool, ant, is still available at http://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".
Java EE App Server
WildFly http://wildfly.org/downloads/ WildFly is the project once known as "JBoss Application Server".
TomEE http://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.