Following are the advantages of Kotlin over Java:-

• Data class: In Java, you must create getters and SETTERS for each object, as well as properly write hashCode (or allow the IDE to build it for you, which you must do every time you update the class), TOSTRING, and equals. Alternatively, you could utilize lombok, but that has its own set of issues. In Kotlin, data classes take care of everything.
• Patterns of getter and setter: In Java, for each variable, you use it for, rewrite the getter and setter methods. You don't have to write getter and setter in kotlin, and if you must, custom getter and setter take a lot less typing. There are ADDITIONAL delegates for identical getters and setters.
• Extension Functions: In Java, there is no support for extension functions. Kotlin on the other hand provides support for extension functions which makes the code more clear and cleaner.
• Support for one common codebase: You may extract one common codebase that will TARGET all of them at the same time using the Kotlin Multi-Platform framework.
• Support for Null Safety: Kotlin has built-in null safety support, which is a lifesaver, especially on Android, which is full of old Java-style APIs.
• Less prone to errors: There is less space for error because it is more CONCISE and expressive than Java.