Null check of Object and Object Chain in Java

null check 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());

  1. 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);
Location: Pune

Comments

Post a Comment

Popular posts from this blog

Functional Programming

Image
Functional programming is a software development paradigm out of various available software development methodology. It is based on function which is nothing but a computation unit and it's result depends on the argument and variable defined in the scope. In computer program, a functional programming treats every computation as an evaluation of mathematical functions and never use mutable data to change it's state. The output value of a pure function depends on the arguments which are input to the function and will produce the same result every time for the same set of inputs.  It means f(x) will always produce the same result y for same value of x. A function is full of functions or declarations instead of statements. Languages: Scala, Python, Erlang, Haskell etc. Various concepts of functional programming : Higher Order Functions First Class Function  Pure Function Immutability     
Read more

Scala Functions

Function : A function is computational unit in a program. Function : To define a function specify - name, parameter, body and return type.   Functions are implicitly declared as abstract if leave off the equal sign and method body. Remove = sign if not to return any thing. A function can have named and optional parameters. Use Unit if the function does not return anything. ( Unit is equivalent to Void in java) Function definition :   def functionName ([list of parameters]) : [ return type ]             Abstract Function :   Ex - def calculation (a:Int, b:String)         Non Abstract Function :    def functionName ([list of parameters]) : [ return type ] = { }              Example -       def calculation ( a : Int, b : Int): Int = {     var sum : Int = 0     sum = a ...
Read more