javaw.exe is the java runtime environment process.
If you run a java application(usually a .jar file .class file) there are 2 main ways of doing this.
1 is by using the command 'java' which will show a command prompt window.
The other is using the 'javaw' command which wont show a command promps windows. It will, however, show error windows when a appication is damaged.
Minecraft is probably still running. Close it, then try to downgrade again.If that doesn't work, close any running programs named javaw using Task Manager or a similar tool.If that doesn't work, restart your computer.
1.Close other windows that your not using 2.Defrag your computer 3.Empty your recycle bin 4.You might have an integrated graphics card -Dedicated graphics cards run minecraft much better 5.In the options under video settings -change render distance to short -change graphics to fast -change performance to power saver 6. go to task manager - go to javaw -right click and go to change priority to high 7. if still lag download game booster For more information on how to improve the performance of Minecraft check out the Related Links section, where I have included a link to site with a tonne of guides on the subject.
Tools provided in java includes, 1. Jar: Mostly used tool of java, it creates jar archive file(executable file by javaw/java if you have jre installed in your system, lib files to import your classes and reuse). 2. Jarsigner: This utility signs a jar, and can verify a signed jar. 3. Keytool: Tool to create keystore and certificates. 4. servertool: Java IDL server tool. 5. Policytool: Edit and create policy, keystore is required for the same. 6. Javah: Tool to create header file. 7. appletviewer: Tool to view applets. 8. HtmlConverter: Convert applet to html. Common uses: java, javac, javaw, javadoc, javap (get the class structure) etc