If you are not sure whether you have Oracle's JDK or JRE installed correctly, please confirm by doing the following:

1. Run a complete directory search (using the 'All File and Folders' option if available) on your drives for the occurrence of 'jdk' in the filename.
2. To confirm correct JRE installation , run a complete directory search (using the 'All File and Folders' option if available) on your drives for the occurrence of  'jre' in the filename.
1. If your results retrieve a folder with the name 'jdk' immediately followed by a series of version numbers (for example, jdk1.8.0_22), then your JDK has been installed. You should double-check the contents of this folder to ensure that the installation files are intact. If you are unsure about this, proceed to step 3 to re-install the JDK. Otherwise, proceed to step 3d to check that your JAVA_HOME environment variable has been set correctly.
2. If your results retrieve a folder with the name 'jre' immediately followed by a version number (for example, jre6), then your JRE has been installed. You should double-check the contents of this folder to ensure that the installation files are intact. If you are unsure about this, proceed to step 4 to re-install the JRE. Otherwise, proceed to step 4d to check that your JRE_HOME environment variable has been set correctly.
3. If you do not retrieve results as explained above, then it is highly likely that your JDK or JRE has not been installed.
3.  To install the JDK, follow these instructions:
1. Go to the Java download page.
2. Download the JDK version 1.7 or 1.8.  will work with either one.
3. When the download has finished, run the Java installer. At one point, you will be asked to choose a directory to install to. Copy or write this directory down for use later.
4. Check that the JAVA_HOME environment variable has been set correctly.
1. Open the 'Start' menu, choose 'Run', type cmd in the 'Run' dialog box and click the 'OK' button.
2. In the command prompt window, type echo %JAVA_HOME% and then press Enter.
3. View the result:
4. If a directory path is displayed that looks similar to one of the following examples, with the letters 'jdk' immediately preceding a series of version numbers, and this path matches the location where you installed the JDK in step 3c, then your JDK has been successfully installed and your JAVA_HOME environment variable has been set correctly. ''Examples of typical JAVA_HOME environment variable values'': 
1. 1. 1. • C:\Program Files\Java\jdk1.8.0_22
         • C:\Progra~1\Java\jdk1.8.0_17
         • C:\Java\jdk1.8.0_17
         • C:\jdk1.8.0_17
5. If nothing is displayed or you do not see 'jdk' immediately followed by a series of version numbers (like one of the examples above), then you need to set the JAVA_HOME environment variable. Please follow these instructions to set your JAVA_HOME environment to the directory where you have just installed the JDK. By default, this directory is under C:\Program Files(x86)\Java for a 32 bit Windows System. You will find it under c:\Program Files on a 64 bit Windows system.
4.  To install the JRE, follow these instructions:
1. Go to the Java download page.
2. Download the JRE version 1.7 (update 21 or greater) or 1.8.  will work with either one.
3. When the download has finished, run the Java installer. At one point, you will be asked to choose a directory to install to. Copy or write this directory down for use later.
4. Check that the JRE_HOME environment variable has been set correctly.
1. Open the 'Start' menu, choose 'Run', type cmd in the 'Run' dialog box and click the 'OK' button.
2. In the command prompt window, type echo %JRE_HOME% and then press Enter.
3. View the result:
4. If a directory path is displayed that looks similar to one of the following examples, with the letters 'jre' immediately preceding a version number, and this path matches the location where you installed the JRE in step 4c, then your JRE has been successfully installed and your JRE_HOME environment variable has been set correctly. ''Examples of typical JRE_HOME environment variable values'': 
• 1. • • • c:\Program Files)\Java\jre1.8.0_20
         • c:\Program Files(x86)\Java\jre7
5. If nothing is displayed or you do not see 'jre' immediately followed by a version number (like one of the examples above), then you need to set the JRE_HOME environment variable. Please follow these instructions to set your JRE_HOME environment to the directory where you have just installed the JRE. By default, this directory is under C:\Program Files\Java for a 32 bit Windows System. You will find it under c:\Program Files (x64) on a 64 bit Windows system.

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