Simple

Java is very easy to learn, and its syntax is simple, clean and easy to understand. According to Sun, Java language is a simple programming language because:

• Java syntax is based on C++ (so easier for programmers to learn it after C++).
• Java has removed many complicated and rarely-used features, for example, explicit pointers, operator overloading, etc.
• There is no need to remove unreferenced objects because there is an Automatic Garbage Collection in Java.

Object-oriented

Java is an object-oriented programming language. Everything in Java is an object. Object-oriented means we organize our software as a combination of different types of objects that incorporates both data and behavior.

Object-oriented programming (OOPs) is a methodology that simplifies software development and maintenance by providing some rules.

Basic concepts of OOPs are:

1. Object
2. Class
3. Inheritance
4. Polymorphism
5. Abstraction
6. Encapsulation

Advantages of Java 

Simple :

• Java is Easy to write and more readable and eye catching.
• Java has a concise, cohesive set of features that makes it easy to learn and use.
• Most of the concepts are drew from C++ thus making Java learning simpler.

Secure :

• Java program cannot harm other system thus making it secure.
• Java provides a secure means of creating Internet applications.
• Java provides secure way to access web applications.

Portable :

• Java programs can execute in any environment for which there is a Java run-time system.(JVM)
• Java programs can be run on any platform (Linux,Window,Mac)
• Java programs can be transferred over world wide web (e.g applets)

Object-oriented :

• Java programming is object-oriented programming language.
• Like C++ java provides most of the object oriented features.
• Java is pure OOP. Language. (while C++ is semi object oriented)

Robust :

• Java encourages error-free programming by being strictly typed and performing run-time checks.

Multithreaded :

• Java provides integrated support for multithreaded programming.

Architecture-neutral :

• Java is not tied to a specific machine or operating system architecture.
• Machine Independent i.e Java is independent of hardware .

Interpreted :

• Java supports cross-platform code through the use of Java bytecode.
• Bytecode can be interpreted on any platform by JVM.

High performance :

• Bytecodes are highly optimized.
• JVM can executed them much faster .

Distributed :

• Java was designed with the distributed environment.
• Java can be transmit,run over internet.

Dynamic :

• Java programs carry with them substantial amounts of run-time type information that is used to verify and resolve accesses to objects at run time.

Disadvantages of java

To start learning or working upon any programming language you must know its strengths and weaknesses so that you can utilize the best things out of it and avoid causing the circumstances that portray in the bad side of the language. Java has also got some drawbacks that you should know before starting over. Let's discuss the cons of using Java.

1. Java is slow and has a poor performance

Java is memory-consuming and significantly slower than native languages such as C or C++. It is also slow compared to other languages like C and C++ because each code has to be interpreted to the machine level code. This slow performance is due to the extra level of compilation and abstraction by the JVM. Moreover, sometimes the garbage collector leads in the poor performance of Java as it consumes more CPU time

2. Java provides not so attractive look and feels of the GUI

Though there are many GUI builders in Java for creating the graphical interface still they are not suitable for creating complicated UI. There are many inconsistencies while using them. There are many popular frameworks such as Swing, SWT, JavaFX, JSF for creating GUI. But they are not mature enough to develop a complex UI. Choosing one of them which can be suitable for you may require additional research.

3. Java provides no backup facility

Java mainly works on storage and not focuses on the backup of data. This is a major drawback that makes it lose the interest and ratings among users.

4. Java requires significant memory space

Java requires a significant or major amount of memory space as compared to other languages like C and C++. During the execution of garbage collection, the memory efficiency and the performance of the system may be adversely affected.

5. Verbose and Complex codes

Java codes are verbose, meaning that there are many words in it and there are many long and complex sentences that are difficult to read and understand. This can reduce the readability of the code. Java focuses on being more manageable but at the same time, it has to compromise it with the overly complex codes and long explanations for each thing.