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Janardhan Pulivarthi
Janardhan Pulivarthi

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Day 8 of 100 - Java: Use cases

Thoughts

The Java is there from a number of years. A lot of articles, docs, solutions are available. I find it difficult to follow what is it that I should learn about.

To my knowledge (hands-on), Java is used for

  1. coding as high-level language for building systems,
  2. compilers (examples, https://github.com/apache/systemds),
  3. Java API Clients (https://cloud.google.com/java/docs/reference),
  4. Building websites (https://github.com/JetBrains/kotlin-web-site)

Java as a API client is powerful.

Space Rocket loading project

https://github.com/j143/java-basic-space-challenge

phase-1.txt

building tools=2000
building tools=2000
building tools=2000
building tools=5000
building tools=5000
building tools=2000
building tools=1000
building tools=5000
building tools=6000
shelter equipment=5000
construction equipment=5000
plants=1000
steel=8000
books=1000
water=5000
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phase-2.txt

habitat=3000
colony=5000
food=5000
habitat=3000
colony=5000
food=3000
colony=5000
food=3000
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static keyword

Static fields

// Person.java
public class Person {
    public static int instanceCount;
    public int localCount;

    public Person() {
        instanceCount++;
        localCount++;
    }

}
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//Main.java
public class Main {
    public static void main(String [] args) {
        for(int i=0; i < 4; i++) {
            Person person = new Person();
            System.out.println("(" + person.localCount + ", " + + person.instanceCount + ")");
        }
    }
}
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output will be: (1, 4)

Static Method

Like static fields, static methods belong to class not objects.

Points:

  1. This is a method independent of the object
  2. A static method takes in input arguments and returns result based on input only nothing else
  3. The static method does not need any field values
  4. But, a static method can still access static fields since they belong the Class
public class Compute {
  public static int add(int x, int y) {
    return x + y;
  }

  public static int subtract(int x, int y) {
    return x - y;
  }
}
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add and subtract methods can be called without creating the object.

Compute.add(2,3);
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Top comments (2)

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sadiejay profile image
Sadie

Wishing you success on your journey to learn Java!

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j143 profile image
Janardhan Pulivarthi

Thanks. :)