Hello LVM, 

Java is actually a very important programming language with wide and efficient usuage. There can actually be no downside to learning JAVA. But despite all its advantages this programming language does have a few low points and they are as follows: 

1. JAVA is comparatively slower

2. JAVA takes more memory space

3. It has language limited latency critical tuning

4. JAVA's architecture code is inefficient

5. It has no means for data back-up

Hope this helps :)