In simplest terms, a String is an collection (referred to in programming as an "array") of characters. If you wanted to have a String that said "Reddit", it would literally be an array of character values ['R', 'e', 'd', 'd', 'i', 't']. The most fundamental difference between strings and primitive types such as "int" are that primitives are single values. Strings are collections of values (specifically, a collection of characters.) Characters themselves are primitive types. In addition, primitive types are pieces of data. Strings are objects, which are instances of classes. As far as classes go...basically, the people who made Java built a lot of code so Strings could be easy to use by programmers. (This is also why "String" is capitalized: the name of the class has a capital S.) Sorry if this is too technical...but it should answer your questions. More on reddit.com

It's not changing the contents of the string, it's creating a brand new string to which the string reference s now refers. The old string contents referred to by s are discarded and garbage collected. This would (if it were allowed in Java, which it isn't) change the contents of a string: String s = "a"; s[0] = 'z'; More on reddit.com

This method is the first method the Java compiler sees in order to start running a program. There is a reason why those keywords are there. Here's why: public public is an accessibility modifier in Java. It means that the method can be accessed by entities outside the scope of the defining class. Since this method needs to be accessed by something outside the class (the compiler) it needs to be public static Having a method static, means that it can be called without needing to make an instance of the class first. The compiler can therefore run the main() method without making an instance of the class it contains it. void Void means that the method doesn't return anything. Since it's the first method run, it doesn't need to return anything to the compiler, and therefore it has been set to void. main The name of the method String[] args This is an array of arguments. These are used when you're running your application on command prompt. I'm sorry this is not ELI5, but I hope this helps More on reddit.com

argument - think of a mathematical function f(x). x is an argument of the function.

method - think of it as a function that may, or may not, use some arguments to work

string - a text basically

array - set of elements in a particular orders, each "slot" in the array has its index (counted from 0 up)

class - theoretical description of some entitie, a definition with attributes and methods.

instance - an object representing class. Eg. you've got a class Cat and your pet named Snowball is an instance of this class. Instances are also known as objects, hence the term"object programming"

public/private - these are characteristics assigned to variables that basically mean that they can be edited freely (public) or only by the class it's defined in (private)

static - a characteristic of a variable/method that pretty much says it's independent from instances of class and you can refer to them by class they belong to, not only by particular instances

void - a characteristic of method that doesn't return anything but just does some operations and maybe changes some values.

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