Week 4: Exception Handling & Collections Framework

This week focuses on handling runtime errors gracefully and mastering Java’s Collections Framework for managing groups of data. Students will also learn how to iterate efficiently using Iterators and Enhanced For Loops.

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Topics Covered

1. Exception Handling

• Understanding different types of errors:

  • Compilation, Runtime, and Logical errors

• Exception hierarchy (Throwable, Exception, Error)

• Checked vs Unchecked exceptions

• Using try, catch, finally blocks

• Throwing exceptions manually with throw

• Declaring exceptions with throws

• Creating custom exceptions

• Best practices for clean, readable error handling

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2. Java Collections Framework

• Purpose of the Collections Framework

• List, Set, and Map interfaces

• Key implementations:

  • ArrayList
  • HashSet,
  • HashMap,

• Understanding:

  • Duplicates and uniqueness
  • Ordered vs unordered collections
  • Accessing elements (by index or key)

• Choosing the right collection for different use cases

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3. Iteration in Collections

• Traversing collections safely and efficiently

• Enhanced For Loop (for-each):

  • Simple traversal for reading data
  • Best for read-only operations

• Iterator Interface:

  • Methods: hasNext(), next(), remove()
  • Safe element removal during iteration
  • Preventing ConcurrentModificationException

• Using forEach() and lambda expressions (Java 8+)

  • Functional style iteration
  • Method references (System.out::println)

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4. Practical Integration

• Combining Collections with Exception Handling (e.g., handling missing keys, empty lists, or invalid data)
• Using Iterators to filter data dynamically
• Nesting Lists and Maps for real-world data modeling

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Activities

• Practice try-catch-finally with different exception types

• Create and handle custom exceptions

• Work with Lists, Sets, and Maps to manage collections of data

• Write programs using Iterators and for-each loops

• Build mini-projects combining OOP and collections concepts:

  • Library Management
  • Movie Catalog
  • Student Grade Tracker

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Learning Outcomes

By the end of Week 4, students will:

• Understand and apply exception handling effectively
• Know when to use checked vs unchecked exceptions
• Be confident using Java Collections (List, Set, Map)
• Traverse collections with Iterators and enhanced for loops
• Write cleaner, safer, and more maintainable Java code

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