What are the differences between the Kotlin language and Java?

Kotlin and Java are two separate programming languages with the following differences:

1. Concise syntax: Kotlin has a more concise syntax compared to Java, reducing redundant code and improving development efficiency. For example, in Kotlin, you can use the keywords val and var to declare read-only and mutable variables, while in Java, you need to use different keywords.
2. Null handling: Kotlin natively supports null handling using nullable types to explicitly deal with null values, avoiding null pointer exceptions. In contrast, Java requires null checks to handle null values, making it more prone to null pointer exceptions.
3. Extension functions: Kotlin supports the concept of extension functions, which allows adding new functions to existing classes, whereas in Java similar functionality can only be achieved through inheritance or composition.
4. Functional programming: Kotlin supports features of functional programming, such as lambda expressions and higher-order functions, which make the code more concise and readable. In contrast, Java has relatively weak support for functional programming.
5. Data classes and singletons: Kotlin provides syntactic sugar for data classes and singleton objects, making it easier and more convenient to define and use these special types.
6. Type inference: Kotlin has more powerful type inference capabilities, allowing it to automatically deduce variable types and reduce the redundancy of type declarations.
7. Interoperability: Kotlin seamlessly interoperates with Java code, allowing direct utilization of Java libraries and frameworks, and the ability to compile Kotlin code into Java bytecode for execution.

In general, Kotlin was designed to address the deficiencies in development efficiency and security that Java has. It retains the strengths of Java while introducing new syntax and features that make development more concise, secure, and efficient.