Java Programming Concepts Quiz

Java Programming Concepts

• Variables: Three types—fields, local variables, and parameters.
  • Fields: Typically declared private, can be static (shared by all objects) or non-static (unique to each object).
  • Local Variables: Exist from declaration to the end of a method or loop. Cannot be declared private/public or static/non-static.
  • Parameters: Passed into method headers; act as local variables.
• Variables store primitive values or references to objects. Fields are usually placed at the top of the class.
• Data Conversion (Casting): Converting data types. Integer.parseInt() converts a String to an integer. Other types can be converted to Strings using the + "" operator.

Looping

• For Loop: Initializes a variable, checks a condition, executes a body, and increments the variable.
• While Loop: Similar to a for loop—can be substituted for each other.
• For-Each Loop: Iterates through each element in an array or ArrayList.

Decisions

• If Statements: Use the if keyword and relational operators.
• Switch Case Statements: Use switch, case, and default keywords; useful in specific situations.

Methods

• Methods: Define an object or class's behavior. Usually public, though helper methods are often private.
• Require a return type and may accept parameters.
• Recursive Methods: Methods that call themselves.
• Method Overloading: Methods with the same name but different parameters/return types.
• Calling Methods: Non-static methods: objName.method(); static methods: className.method(). Methods are generally placed at the bottom of the class.

Classes

• Classes: Pieces of Java code. Requires at least one class with a main method. Can be concrete (all methods defined) or abstract (some methods only have headers). The Object class is concrete.

Error Types

• Syntax Errors: Similar to grammar errors; prevent compilation.
• Run-time Errors: Occur during program execution; example: dividing by zero.
• Logic Errors: Code runs but produces incorrect results.

Arrays

• Arrays: One-dimensional or multi-dimensional data structures. Store multiple variables for systematic access and processing.
• Array Indexing: Checked at runtime for validity.
• Array Length: Accessible as an attribute; arrays are not resizable (must create a new array).

Inheritance/Interfaces/Abstract Classes

• Inheritance: Creates superclasses and subclasses to avoid code duplication and improve organization. Fields and methods are inherited, but not constructors. Use super() to call superclass constructors.
• Interfaces: Contain public abstract methods (public and abstract keywords omitted). A class can implement multiple interfaces.
• Abstract Classes: Contain abstract methods (only the method header) and may have concrete methods as well.

File I/O and XML

• Files: Stream (write or read, not both simultaneously) or random access (write and read in different places).

Software Development

• Software Development Life Cycle (SDLC): Five phases.
  • Analysis: Defining the problem, scope, and requirements (who, how, data).
  • Design and Development: Designing algorithms, breaking into subtasks. Can include pseudocode, flow charts, or IPO charts.
  • Implementation: Writing code and producing documentation (longest phase).
  • Testing: Using various input data, thorough testing of operations.
  • Maintenance: Updating and incorporating changes after launch.

Software Scope Document

• Problem Statement, Project Background, Stakeholders, Users, Risks, Assumptions all included in the document.
• Vision of the Solution: includes a vision statement, list of features, phased release scope (optional), features not included.

Terminology

• Comprehensive list of programming concepts covered.