Import statement usage in Java - Step-by-Step Execution

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Concept Flow - Import statement usage

Start Java file

↓

Write import statement

↓

Compiler reads import

↓

Imports class/package

↓

Use imported class in code

↓

Compile and run program

The Java compiler reads import statements at the top of the file to know which classes or packages to include before running the code.

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Execution Sample

Java

import java.util.ArrayList;

public class Test {
  public static void main(String[] args) {
    ArrayList<String> list = new ArrayList<>();
  }
}

This code imports the ArrayList class and then creates an ArrayList object in the main method.

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Execution Table

Step	Action	Evaluation	Result
1	Read import statement	import java.util.ArrayList;	ArrayList class is available to use
2	Start main method	public static void main(String[] args)	Program ready to run main
3	Create ArrayList object	ArrayList<String> list = new ArrayList<>();	list variable holds new ArrayList
4	End main method	}	Program ends successfully

💡 Program finishes after main method ends

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Variable Tracker

Variable	Start	After Step 3	Final
list	undefined	new ArrayList object	new ArrayList object

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Key Moments - 2 Insights

▶Why do we need the import statement before using ArrayList?

▶Can we use ArrayList without import if we write full name?

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Visual Quiz - 3 Questions

Look at the execution table, what happens at Step 1?

A The program creates an ArrayList object

B The import statement is read and ArrayList becomes available

C The main method starts running

D The program ends

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Concept Snapshot

Java import statement:
- Placed at top of file
- Syntax: import package.ClassName;
- Makes classes available without full name
- Needed before using external classes
- Helps keep code clean and readable

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Full Transcript

In Java, the import statement is used at the top of the file to tell the compiler which classes or packages to include. For example, importing java.util.ArrayList allows you to use ArrayList directly in your code. The compiler reads the import first, then runs the main method where you can create objects of the imported class. Without the import, the compiler will not recognize the class and will give an error. You can also use the full class name without import, but import makes the code shorter and easier to read.