Having a really hard time getting my head around method chaining in java. Help appreciated.

Question

I understand the results of it but not the concept itself, and no past post here or internet search seems to answer my question, so I’ll now lean on the TTH community now.
So my main question is WHY is it possible to chain methods? Is it because methods can become objects upon which you can call more methods? 
Example: 
String myName = "Neros";
myName.toLowerCase().toUpperCase();  // returns "NEROS"
As I understood it methods can ONLY be called upon (|| exclusive to) objects, is this true? and 
does that mean that the entire  expression MyName.toLowerCase(). Is an object? I vaguely read while searching that it’s because methods like toLowerCase delivers a string (in this case “neros”) which is an object, so it’s essentially chaining on the returned String objects of a method? is this correct or am I completely lost?
Additional questions:
-If methods are not exclusive to objects, I wondered if you can call one on a String Class, even chain them? 
Example :  String.add.subtract(3,1) = 2 
-if yes where would you apply class method chaining?
-Do all methods need dot operators ? ----"String add(x,y)?
-Can you chain on primitive data methods/fuctions like parseInt();?
Again. any help is greatly appreciated. The more detailed the better! 
Reference: I'm on the first video of the Java Objects course with Craig at m5:30 where he briefly mentioned method chaining.

Mohammad Laif · Accepted Answer

Methods are objects (everything is object even classes).
As I understood it methods can ONLY be called upon (|| exclusive to) objects, is this true?
You can call method on your object like myName.toLowerCase(). And you can call method without using object, by them self like printAwesomeName(); and you can call method on method, and calling method on class too, each object has its own method.
so it’s essentially chaining on the returned String objects of a method? is this correct or am I completely lost?
Yep. For your information, in Java 8 there is something awesome called Stream doing exactly what you meant.
Additional questions: -If methods are not exclusive to objects, I wondered if you can call one on a String Class, even chain them? Example : String.add.subtract(3,1) = 2
From my knowledge each class has its own method, Also there is Reflections! (methods) I used them in Android Development. Examples to know my class name:
java
MainClass.class.getSimpleName();
MainActivity.this.getClass().getSimpleName();

if yes where would you apply class method chaining?
from above example!
Sorry I could not understand the rest questions, but I had same questions when I start to learn programming, I could say to you just don't rush your self, or your mind will get overwhelmed.

Kalea Wolff · Answer

So, method chaining is the use of more than one method at a time. It will still follow the rules of using a method (dot notation). It allows you to be more  efficient in your code later once you've built your own methods. But out of the box, you can chain methods together to do fun stuff. 
Say we have a String as given in your example. You lowercased and immediately uppercased it. But we wanted to return it differently to the  user (or server as is frequently the case). We can't often trust users to give us valid input. So in this case, let's fix it before we return it. 
String myName = "   Neros  " ;
Note the intentionally included spaces. 
public String lowerChangeLetterAndRemoveSpaces (String name)  {
  return name.toLowerCase().replace('N', 'H'). trim();
} 
This will return 'heros' when we call. lowerChangeLetterAndRemoveSpaces(myName). 
I know this was quick and dirty, but I hope it helps you.

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Neros E.

Neros E.

Having a really hard time getting my head around method chaining in java. Help appreciated.

2 Answers

Mohammad Laif

Mohammad Laif

Neros E.

Neros E.

Kalea Wolff

Kalea Wolff

Neros E.

Neros E.