Java9 – new features

  • More Module System, e.g.  self-describing collection of code and data
    • Using jlink, to introduce a new optional phase, link time, which is in-between compile time and run time, during which a set of modules can be assembled and optimized into a custom runtime image
    • The modular JAR file with module-info.class file in its root directory.
    • Using jmod tool, the New JMOD format can be created. (new packaging format similar to JAR)
  • New version schema ($MAJOR.$MINOR.$SECURITY.$PATCH)
  • java shell: jshell
  • Compile for old java version (6 – java6)
    javac -source 6 -target 6
  • More Diagnostic Commands: jcmd (jcmd pid help command)
  • Multi-Release JAR Files: Extends the JAR file format to enable multiple, Java release-specific versions of class files to coexist in a single archive
  • Removes the hprof, jhat from the JDK
  • More Security: DTLS, TLS,  disable X.509 certificate chains with SHA-1-based signatures,  PKCS12 keystores by default, SHA-3 cryptographic hash functions
  • The Garbage-First Garbage Collector (G1 GC) is the default garbage collector in JDK 9.
  • JavaDB, which was a rebranding of Apache Derby, isn’t included in JDK 9.
  • The launchers java-rmi.exe from Windows and java-rmi.cgi from Linux and Solaris have been removed.
  • In JDK 9, the Windows 32–bit client VM is not available. Only a server VM is offered.
  • Java VisualVM isn’t bundled with JDK 9.
  • The AppleScript engine is removed in JDK 9.

Windows Registry Key Changes

The Java 9 installer creates these Windows registry keys when installing the JRE:


The Java 8u152 installer creates these Windows registry keys when installing the JRE:

  • “HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment”
  • “HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment\1.8”
  • “HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment\1.8.0_152”

Firefox 52 not supported to java plugin

From Firefox Version 52, (the standard version), the support to java plugin has ended, except for Adobe Flash.


Workaround (until 2018):
Install the 32bits of Firefox Version 52 ESR (Extended Support Release)


Jenkins 2.23.2 LTS

CI Server – Jenkins 2.23.2 LTS in Technosynoptic

Testing with the last version of JDK – jdk 1.8.0_u121 and Ubuntu 14.04.5 LTS

java version “1.8.0_121”
Java(TM) SE Runtime Environment (build 1.8.0_121-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.121-b13, mixed mode)

Running with own container
java -jar jenkins.war







Migrating from Tomcat 6x to 7x

The official guide from Apache

Migrating from 6.0.x to 7.0.x

Apache Tomcat 7.0.x requires Java 6 or later. Apache Tomcat 6.0.x required Java 5.

Details in