JDK : Java Glossary

Introduction

Version 1.9 is out, but I could not get it to install.

JDK (Java Development Kit). Formerly foppishly called the SDK (Software Development Kit). It is free and you may freely distribute any programs you create with it.

• The last 1.7 JDK version was 1.7.0_79. There is another later version 1.7.0_76 which contains additional optional fixes, but Oracle recommends you not use it unless you are having the troubles it fixes.
• The current version for 1.8 JDK is 1.8.0_131.
• JET (Just Enough Time) 11.3 supports up to Java 1.8.0_131.

Which Java.exe?

When you install multiple JREs (Java Runtime Environments)and JDKs (Java Development Kits) you will have many different java.exe, javaw.exe, javaws.exe and javac.exe installed. Which one is used depends on which JREs and JDKs you have installed, which JVMs are enabled in the Java Control Panel, the SET JAVA_HOME, the path, the current directory and the phases of moon used in a pseudo random number generator to select one of the installed Javas. Verify you are using what you expect with java.exe -version.

To further confuse you, Oracle refers to the various downloads of Java updates. They are not updates, but entire new versions. You don’t need a previous version installed.

To use the JDK you must be running W2K, XP, W2003, Vista, W2008, W7-32, W7-64, W8-32, W8-64, W2012, W10-32, W10-64, Linux, LinuxARM, LinuxX86, LinuxX64, Ubuntu, Solaris, SolarisSPARC, SolarisSPARC64, SolarisX86, SolarisX64 and OSX.

32 or 64 bit?

The fewer JVMs (Java Virtual Machines) you have installed the better. If you have a 32-bit Windows, install just a 32-bit JDK. It will as a side effect install a 32-bit JRE. If you have a 64-bit Windows, install first a 64-bit JDK. It will as a side effect install a 64-bit JRE. Then install IntelliJ. Then if you need Java to run Applets in your browser, install a 32-bit JRE. Don’t Install any 1.7 JDKs or JREs. Set up your JAVA_HOME to use the 64-bit JDK and the path to use the 64-bit JRE. It is important to install the 32-bit JRE last so your browsers can find it. Set up the association for *.jar to use the 32-bit java.exe.

Downloading the JDK

Below is how to get Java for Windows, Linux and Solaris. For other platforms (e.g. various Unices) see your OS (Operating System) vendor’s site. For example for NetBSD Unix Java is included in pkgsrc (the Packages System).

rem compiling with JDK 1.8 features turned on
javac.exe -source 1.8 -target 1.8 MyProg.java
rem -30-

Polishing and Testing The JDK Install

1. Click start ⇒ Control Panel ⇒ Java. Make sure all your JREs/JDKs are registered there. If not ask it to find and register them. Remove any JREs/JDKs you are not using.
2. Configure your set environment for the CLASSPATH. If you are not sure use CLASSPATH=. See environment for details of how. See classpath for details.
3. Configure environment variable JAVA_HOME= J:\Program Files\java\jdk1.8.0_131\ to point to the JDK.
4. Configure environment variable PATH to include the JDK binaries directory J:\Program Files\java\jdk1.8.0_131\ bin\. This ensures that javac.exe is on the path. See path for details.
5. Set your JAVA_HOME environment variable to the JDK directory e.g. J:\Program Files\java\jdk1.8.0_131\ . Some software such as Caucho Resin finds Java using this variable rather than poking around in the registry. See environment for details on how to set it.
6. Install unlimited strength encryption per these instructions.
7. Configure *.jar files to be executable and clickable, so you can run them just by typing their names on the command line or double clicking them in the explorer. See making jar files executable and double clickable for details on how to set up the necessary association.
8. Copy your various library jars into the J:\Program Files\java\jdk1.8.0_131\ jre\lib\ext\ directory.

   Sooner or later you will have to reinstall the JDK/JRE and you will lose your ext directories. You can quickly rebuild them if you maintain a bat file like this and run it after every JRE/JDK install. Adjust the file to account for where your ext dirs are and where the jars are you need.

9. Set up your J: drive to point to the drive where you installed the JDK. For detailed instructions see J: drive.
10. The JDK contains a JRE. Test the JRE the same way you would had you downloaded a standalone JRE.
11. Type java.exe -version. You should see Java version 1.8.0_131 .
12. Type javac.exe -version. You should see javac 1.8.0_131 .
13. Compile and run a HelloWorld application.
14. Fix any bookmarks in your browser into the JDK locally or at Oracle.
15. If you can’t get it to work, follow the failed install instructions.

Installing under Linux

To access the JDK under Linux, you need to set up two environment variables JAVA_HOME and the PATH.

Contents of The JDK

• In the J:\Program Files\java\jdk1.8.0_131\ directory you will find src.zip/ src.jar which contains the source to the Java core libraries.
• In the J:\Program Files\java\jdk1.8.0_131\bin directory you will find javac.exe, java.exe, javaw.exe, javaws.exe and javadoc.exe. and other utilities like: keytool.exe pack200.exe policytool.exe and unpack200.exe.
• In the J:\Program Files\java\jdk1.8.0_131\lib directory you will find the jar files, especially dt.jar/ rt.jar/ classes.zip which contains most of the Java core library class files. Oracle likes to rename this file frequently.
• In the J:\Program Files\java\jdk1.8.0_131\jre\bin directory is a duplicate of the crucial J:\Program Files\java\jdk1.8.0_131\ bin files that are also distributed separately bundled in the JRE, e.g. java.exe, javaw.exe, javaws.exe, keytool.exe pack200.exe policytool.exe and unpack200.exe. but not the developer tools such as javac.exe or javadoc.exe including Java Web Start. In jre\lib\ext you can put jars you want automatically included on the path.
• In C:\Program Files\java\jre1.8.0_131\bin is yet a third copy of the crucial files, a duplicate of the JRE, including java.exe, javaw.exe, javaws.exe, keytool.exe pack200.exe policytool.exe and unpack200.exe. but not the developer tools such as javac.exe or javadoc.exe

Why Three Copies of the Executables?

1. The C:\Program Files\java\jre1.8.0_131\\bin version is for ordinary production client use.
2. The J:\Program Files\java\jdk1.8.0_131\\jre\bin version is for production servers. The java.exe there understands the -server option.
3. The J:\Program Files\java\jdk1.8.0_131\\bin version is for debugging.

For client use, you don’t need to put anything on the path. The JRE installer puts a dummy copy of java.exe on the path in C:\WINNT\system32 to get things started. When it is invoked, it looks in the registry to find the current actual java.exe. javaws.exe works the same way.

Caveats

• Oracle downloads often fail because they give them the non-standard MIME (Multipurpose Internet Mail Extensions) type of magnus-internal/cgi. Set your browser to treat this MIME type just like application/octet-stream to simply download the files.
• Note, Oracle’s install instructions for the older releases may tell you to hit download software. There is no such button. Hit continue instead. The JDK package optionally upgrades your Winsock. Undo with C:\Windows\WS2BACKUP\WS2BACKUP.BAT or remove/reinstall Win95 dialup networking. The new socket software did not work for me and for a few other people I talked to. Plan your recovery before you install. Without a working Winsock you won’t be able to ask for help or go searching the net for a solution.
• JDKs sometimes don’t include the javax packages (except for Swing). You must download those separately. I have provided additional help  finding jars, namely where to download additional jars.

Failed Installs

1. Check that the JDK/JRE download is the expected size. The download may have aborted.
2. For Java Applets to work in a browser, there must be a copy of msvcr71.dll in the C:\Windows\system32 folder. If there isn’t, copy it from C:\Program Files\java\jre1.8.0_131\\bin.
3. Make sure that the anti-spyware program Webroot SpySweeper, is turned off. It will interfere with installs.
4. Make sure no copies of any of the Java utilities are running. Use the task manager to kill any that won’t quit normally.
5. Uninstall all Java JDKs and JREs with Start ⇒ Settings Control Panel ⇒ add/remove programs.
6. Reboot.
7. Manually delete any remaining files in the C:\Program Files\java\jre1.8.0_131\, J:\Program Files\java\jdk1.8.0_131\ and C:\Users\user\AppData\LocalLow\Sun\ directories. Make sure there are no copies of java.exe, jawaws.exe, jawaw.exe or javac.exe anywhere on your machine including C:\Windows\System32.
8. Manually delete any *.msi files for Java buried in the C:\Windows\ tree. Click search ⇒ Files and Folders ⇒ *.msi to track them down.
9. Go into the registry with regedit.exe and delete all reference to the Java installation i.e. HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft. If you are not sure, leave the entry alone.
10. Delete all the files in "C:\Documents and Settings\user\Application Data\Sun\Java\" or your equivalent, such as C:\Users\user\AppData\LocalLow\Sun\ , C:\Users\user\AppData\Roaming\Sun\ and C:\Windows\Sun\. You might have to reboot to free locks to let you kill the directories.
11. Run a registry cleaner such as Ace to get rid of any registry references to the deleted files.
12. Reboot.
13. Reinstall, including setting up the set JAVA_HOME, set CLASSPATH, set PATH environment and the ext directory.
14. Sometimes uninstall, install to a different directory, uninstall, install to the original directory will clear it.
15. If Java runs standalone, but does not work in your browser, test your JRE browser hooks by running Wassup. It should tell you that your browser is using the JVM (Java Virtual Machine) version you just installed. Look for the line marked java.version. If Wassup does not run, or you have the wrong version, go into Start ⇒ Settings Control Panel ⇒ Java Plug-In ⇒ Browser and turn off each browser, then click apply, then turn them on again, then hit apply again. Then retest with Wassup.
16. Have a look at the hidden Java Web Start control file "C:\Documents and Settings\user\Application Data\Java\Deployment\deployment.properties". Don’t edit it. If you see something wonky (e.g. references to an uninstalled JVM ), go into the Control Panel ⇒ Java Control Panel and turn things off and on again and hit apply to refresh the file. If that does not work, make a backup and try deleting the deployment.properties file, then try going into the Java Control Panel and clicking reset. The set everything up from scratch. If that does not work try editing a copy of the original deployment.properties file, sorting the entries first to make it clearer what they do and installing it back as the official deployment.properties.

JDK Differences

Upgrading Your JDK to a New Version

1. Download and install the new JDK.
2. Check your set environment for outdated references, e.g. JAVA_HOME, classpath, path.
3. Update any *.bat files that point to the old JDK/JRE to point them to the new JDK/JRE.
4. Copy your various auxiliary jars into the ext directory. See ext directory for details.
5. Reconfigure the compiler used in your various IDE project settings, update library includes, e.g. tools.jar and recompile everything.
6. Move the doc documentation from your old JDK to the new one
7. Check that the association for *.jnlp is set up to point to the new javaws.exe in both Windows and your browser. See installing Java Web Start for details.
8. If you use SlickEdit, copy src.zip to scr.jar and reindex it.
9. If that does not work, uninstall all JDKs and JREs. Then manually remove any vestigial directories. And start over.
10. If that does not work, clean out the Java registry entries and all the JDKs and JREs and start over. Closures, pauseless garbage collection.

Here is what I do when Oracle releases a new version of the JDK. For you, it is simpler:

1. Notice update in Vercheck and configure new Vercheck version.
2. Tell everyone on com.lang.java.programmer about the new version.
3. Download and install the 64-bit JDK and 32-bit JRE.
4. Download and install Java docs.
5. Adjust and run search/replace script to update version 6 and 7 version numbers in all bat, java, html, xml, jnlp etc. files.
6. Adjust fixext.btm and run it to build environment sets and construct ext libraries.
7. Manually patch web pages about the JDK and JRE and the Java source code that records Java version into.
8. Configure IntelliJ with new JDK.
9. Tidy all source code (4-step process).
10. Rebuild, clean compile everything the new javac.exe.
11. Uninstall the old JDK and JRE. Prune the remnants.

RFE (Request For Enhancement)

• Show all installed JREs in the Java control Panel
• Do whatever it takes to make Java Applets and Java Web Start work in all installed browsers without further tweaking.

Books

Book referral for Java SE 8 for the Really Impatient

	recommend book⇒Java SE 8 for the Really Impatient
	by	Cay S. Horstmann	978-0-321-92776-7	paperback
	publisher	Addison-Wesley Professional	B00HSH2QT6	kindle
	published	2014-01-24
This is not a book to learn Java. It is for programmers already familiar with JDK 1.7 to learn the new features of JDK 1.8. Readers praise it for its lack of fluff and for focusing on new material, not reviewing what everyone already knows. Horstman has written many other well-regarded text books.
Online bookstores carrying Java SE 8 for the Really Impatient abe books anz abe books.ca abe books.de amazon.ca amazon.de Chapters Indigo amazon.es Chapters Indigo eBooks iberlibro.com abe books.com abe books.fr amazon.com amazon.fr Barnes & Noble abe books.it Nook at Barnes & Noble amazon.it Kobo junglee.com Google play abe books.co.uk O’Reilly Safari amazon.co.uk Powells other stores
Greyed out stores probably do not have the item in stock. Try looking for it with a bookfinder.