Professionally I have some clients who cannot work without Java enabled.
However, for home use it is hard to say if you need it or not. I know when I disabled Java on my personal PC I lost YouTube, ability to download from Microsoft and Symantec using their download utilities. A lot of functionality we take for granted on out PCs utilizes Java to run.
So, what do you do if you need Java.
First, delete all Java from your PC. See link below for instructions. Then install the most current version of Java. http://java.com If you have problems downloading from Java.com, because they need Java installed to use their assisted download you can find it easily at www.filehippo.com.
From this point on make sure you update Java every time Java indicates there is an update available.
NOTE: Both Java and Acrobat share the fact that there are both designed to work across many platforms. Microsoft, Mac, Unix, mobile devices, ect. Criminals and malware developers are using this feature because they can create their malware once and distribute it across all platforms using Java or Acrobat PDF files as the carrier. Both Acrobat and Java developers know this and are continually updating Java and Acrobat to thwart the malware developer’s effects. So it is very important that you apply all Java and Acrobat updates as soon as these updates are released. The same is true of whatever web browser you use. Apply browser updates as soon as they are released.