Java Data Types

Java Data Types 

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1. Primitive Data Types (8 Types)

These store simple values, not objects.

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a. byte – 🧮 Small whole number

• Size: 1 byte
• Range: -128 to 127
• Declaration:

  byte retryCount = 3;
  

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b. short – 📦 Medium-range whole number

• Size: 2 bytes
• Range: -32,768 to 32,767
• Declaration:

  short sessionTime = 1200;
  

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c. int – 🔢 Common whole number type

• Size: 4 bytes
• Range: Large range
• Declaration:

  int totalTests = 500;
  

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d. long – 🗃️ Very large whole numbers

• Size: 8 bytes
• Must end with L
• Declaration:

  long executionId = 12345678900L;
  

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e. float – 🌊 Decimal number (less precise)

• Size: 4 bytes
• Must end with f
• Declaration:

  float loadTime = 3.45f;
  

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f. double – 🌐 Decimal number (more precise)

• Size: 8 bytes
• Declaration:

  double responseTime = 125.789;
  

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g. char – 🔤 Single character

• Size: 2 bytes
• Declaration:

  char status = 'P';  // 'P' for Pass
  

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h. boolean – ⚙️ True or False

• Size: 1 bit
• Declaration:

  boolean isTestPassed = true;
  

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2. Non-Primitive (Reference) Data Types

These refer to objects and more complex structures.

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a. String – ✉️ Sequence of characters

• Declaration:

  String browser = "Chrome";
  

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b. Array – 📚 Collection of values

• Declaration:

  int[] testCaseIds = {101, 102, 103};
  String[] browsers = {"Chrome", "Firefox", "Edge"};
  

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c. Class & Object – 🧱 Custom types

• Declaration:

  class TestCase {
      String name;
      boolean isPassed;
  }
  
  TestCase tc1 = new TestCase();
  tc1.name = "Login Test";
  tc1.isPassed = true;
  

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Bonus Tip for QA Automation

Use:

• boolean for assertion flags
• int for counts like number of tests
• String for test data and messages
• double for performance metrics
• Arrays or Lists for data-driven testing

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