I have to create a class called MakeMap with a single static method called countLetters(). The method should take as a parameter a word formed of lowercase letters and return a map of the counts of …
Tag: class
How to create a new object of Public Class
I am a newbie in Java, although I have knowledge of Object Oriented Programming from Python but I’m currently having problem understanding this example on creating public class either combining the …
How do I break up words in a String ArrayList in Java and then reverse them?
The title may sound confusing. Simply, I have a file that have text inside of it. I used a scanner to read that text. I stored that text into an ArrayLists that is a String. The problem I have is that I need to make a method reverses the text in that ArrayList. The text does reverse, but not completely.
Does final variables occupy memory on a per-instance basis?
I have read other question-answers regarding final instance variables and i came to knew that non-static final instance variables are created in heap for every instance of the class but in java -the complete reference by herbert schildt it is said that : Variables declared as final do not occupy memory on a p…
What is the purpose of a static method in interface from Java 8?
Why are static methods supported from Java 8? What is the difference between the two lines in main method in below code? As we can see above, I is not even implemented in B. What purpose would it serve to have a static method in an interface when we can write the same static method in another class and call
Does a class without methods have a special name?
What is a class without methods called? I’m trying to understand and learn about classes, so i have the following class “Variables” that doesn’t have methods, only fields, like the field “Server” in a folder called “utilities”: then this class is called from a m…
The object-oriented approach to a many-to-many relationship
I’m battling at the moment in trying to understand how to approach this issue in an object-oriented way. With a many-to-many relationship such as Students-Subjects, where each student gets a mark for a certain subject, assuming the following: I want to be able to display all the marks for a given studen…
Can a object be private and public?
Can a reference to an object be private in class while other object can have a public reference to the same class(post script: new to java+ a simple example please). I read somewhere that this prob is regarding aliasing? Sorry my title may not make sense! Answer Objects aren’t private or public. Fields …
How can we use .class on primitive types?
When we say it prints class java.lang.Integer which makes sense because java.lang.Integer is a class. So we can have a corresponding Class object. But when I do it prints int which I felt is kind of ambiguous as .class returns an object of type Class and int is not a class (but a primitive type). What is the …
What does “Could not find or load main class” mean?
A common problem that new Java developers experience is that their programs fail to run with the error message: Could not find or load main class … What does this mean, what causes it, and how should you fix it? Answer The java <class-name> command syntax First of all, you need to understand the c…