In Java, every variable has a data type. The data type specifies the type of values the variable can store.

#   
## The `var` keyword
Java 10 introduced a new way to declare variables using the **`var`** keyword.

The following is an example of **variable declaration** using `var`:

```
var name = "John Doe";
```


How does Java determine the type of a variable declared with the `var` keyword? The answer is simple. Java automatically infers the type of a variable using the initial value assigned to a variable declared with `var`.

In the variable declaration above, Java infers that the type of the `name` variable is a `String`.

Due to this automatic inference of the type of a variable, it is necessary to always assign an initial value to the variable.

For example, the following is not allowed:

```java
var name;   // ERROR
```

# 
## Code example
The following is an executable example that shows the `var` keyword in action.

class main {
  public static void main(String[] args) {
    // Int
    var x = 10;

    // Double
    var y = 2.10;

    // Char
    var z = 'a';

    // String
    var p = "John";

    // Boolean
    var q = false;

    // Type inference is used in the var keyword in 
    // which it automatically detects the data type 
    // of a variable
    System.out.println(x);
    System.out.println(y);
    System.out.println(z);
    System.out.println(p);
    System.out.println(q);
  }
}

java10

One good thing about the `var` keyword is that it removes the duplication of the type of a variable, as shown below:

```java
// Without var
Student stu = new Student();
// With var
var stu = new Student();
```

## Limitations of `var`

Although a really useful feature, `var` does have some limitations. Some of them are mentioned below:

- We cannot use it to declare local variables inside methods. We cannot use it to declare method parameters or instance fields.

- We cannot use it to specify the return type of a method.

- We cannot use it with a generic type.

   ```java
   var<String> names = new ArrayList<String>(); // ERROR
   ```

What is the var keyword in Java?

The var keyword

Code example

Limitations of var

The `var` keyword

Limitations of `var`