Most Commonly Used: 
According to Oracle, three billion devices run on Java.  And, because of its real-world applications, it consistently ranks at the top of the TIOBE Programming Community Index. 

Great Career Choice: 
Some of the fastest-growing salaries in the U.S. in 2018 are for Java developers.  (Glassdoor)  

Android Apps Development:
Developers predominatly use their Java skills in building apps for Google's Android. The Android platform is the number one mobile paltform in the world

It Can Run On Any Platform:
Java can compile on Windows and run the same compiled file on Linux, Windows and Mac.

Great Supporting IDE's:
Over the years, coding in Java has become simpler with the introduction of open source development tools, i.e. Eclipse and NetBeans that use Java capabilities for debugging.  
 

Uses a Lot of Memory:
Performance can be significantly slower with Java and more memory-consuming than natively compiled languages such as C or C++.

Difficulty in Learning: 
Learning Java can be a bit challenging if you are a beginner.  However, once you get the hang of Object Oriented Programming and a decent grasp of the syntax, you will be well on your way.

Slow Start Up Times:
There is quite a bit of one-time initialization done by JDK classes before compiling as well as loading classes and verification (making sure code doesn't do evil things, all of which takes longer that some other languages such as C. 

Verbose and Complex Code:
Long, over-complicated sentences make code less readable and scannable. Compare to let's say Python, we can see how clear Python code appears: It doesn’t require semicolons; uses “and,” “or,” and “not” as operators instead of Java’s “&&,” “||,” and “!”; and generally has fewer bells and whistles such as parentheses or curly braces.

Commercial License Cost:
Companies have to prepare for the changes that Oracle will institute in 2019 . Today, the current version of Java is free and available for redistribution for general purpose computing. However, If you are a DEVELOPER, Oracle recommends you review the roadmap information for Java SE 8 and beyond and take appropriate action depending on the type of application you develop and your distribution mode.