Null check of Object and Object Chain in Java

JDK 7 and earlier:

1. Avoid using null check in if statement.
2. Use ternary operator for null/exist check and assign a default value before using.
3. This will make the code clear and more understandable as comparable to using multiple if, else  statements.

JDK 8 and above :

1. Java-8 provides improved API to deal with object null check.
2. Use isPresent() function available in Java.util.Optional interface for null check of single object.

Ex –

Employee employee = new Employee();

employee.setName("Pramoda");

// Getting optional value

Optional<Employee> optionalEmployee = Optional.ofNullable(employee)

.map(Root::getEmployee);

System.out.println("Is Employee present : +optionalemployee.isPresent());

3. Use Java.util.Optional functional interface for object null check and assign default value to avoid null pointer exception.

Ex –

Employee employee = new Employee();

employee.setName("Pramoda");

employee.getDepartment();

// Getting optional value

Optional<Employee> optionalEmployee = Optional.ofNullable(employee);

//Set default value if the input object is null.

Employee employee = Optional.ofNullable(employee)

.map(Employee::getEmployee).orElse(new Employee());

//Set default value if the input string is null 

String name = Optional.ofNullable(employee)

.map(Employee::getName).orElse("Set default value");

System.out.println("Is employee present :"+optionalemployee.isPresent());

System.out.println("Employee object : "+employee);

System.out.println("Employee Name : "+name);