http://en.wikipedia.org/wiki/Java_(programming_language)
In order to understand the difference between high-level programming languages and lower level languages you might have to have a deeper knowledge of computers than you currently have, although I can try to the best of my ability to explain it simply.
Lower level programming languages are more directly related to the actual
machine language that the computer ends up reading in the end. Higher level programming languages are less representative of the actual machine code, and as a result may require either a more advanced
compiler or may require being compiled several times. Generally higher-level programming languages are easier for the user to write in than lower-level languages.