Week 1 - Java

Concepts

• Environment: PATH, CLASSPATH, JAVA_HOME, command vs flags vs args
• Platform Independence: JVM
• Memory model: Stack, Heap, String Pool, Garbage Collection, Concurrency
• Compile time vs Runtime: Source code vs Bytecode
• Object Oriented Programming: Polymorphism, Encapsulation, Inheritance, and Abstraction
• Source Code Management: Gitflow
• Project, Dependency, Build Management
• Unit testing: Test Driven Development, Red-Green-Refactor

Tools

• JDK: javac, java, jar
• Git
  • Gitflow: init, add, commit
  • Branching & Merging: checkout, merge
  • Local & Remote Repositories: clone, remote, pull, push
  • Git vs GitHub
• Maven (mvn)
  • Project Object Model (POM) XML manifest file
  • Management: clean, archetype:generate, exec
  • Build Lifecycle: compile, test, package
• JUnit
  • Assert API
  • Annotations: @Test, @Before, @After

Language Features

• Default Constructor
• Overloading and Overriding
• Checked vs Unchecked Exceptions
• Variable scopes: class/global, object/instance, method, block/loop, bracket
• Interfaces: functional vs marker, default fields & methods
• Abstract Classes
• Anonymous Classes
• Lambdas & Streams
• Generics: type inference, type erasure, bounded types

Language Syntax

• Package & Import
• Class & method signatures: parameters, access modifiers, return types, constructors, varargs
• Access modfiers: public, protected, (default), private
• Non-access modifiers: static, final, abstract, synchronized
• Control statements: if, if else, else, while, do/while, for, switch, continue, break
• Primitive types: byte, short, int, long, char, boolean, float, double
• Reference types: Classes, Enums, Interfaces, Arrays
• Inheritance: extends, implements
• Exception handling: try, catch, finally

Standard Library

• java.lang
  • Object: toString(), hashcode(), equals(), finalize(), notify()
  • String, StringBuilder & StringBuffer
  • Wrapper Classes: Integer, Double, etc.
  • Iterable: forEach()
  • Comparable: compareTo()
  • AutoCloseable (try-with-resources): close()
  • System: in, out, getenv(), gc()
  • Runnable & Thread: run(), start(), isAlive(), join()
  • Reflection: java.lang.reflect, Class
  • Throwable: Error, Exception, RuntimeException
• java.io
  • File
  • InputStream/OutputStream vs Reader/Writer
  • BufferedReader & BufferedWriter
  • Serializable
  • ObjectInputStream & ObjectOutputStream
• java.util
  • StringTokenizer
  • Scanner
  • Properties
  • Java Collections Framework:
    • Arrays
    • Collections
    • Collection:
      • Map: Hashtable, HashMap, TreeMap
      • List: ArrayList
      • Set/SortedSet: HashSet, TreeSet
      • Queue
      • Deque
    • Iterator
    • Comparator

Design patterns

• Singleton
• Factory
• Dependency Injection
• Data Access Object

Questions

• What is Java?
• What are the benefits of Java?
• What is the difference betwwen the JRE, JDK, and JVM?
• What happens during the compilation process?
• What is a constructor?
• What are the primitive datatypes?
• What is a no args constructor?
• What is the default ocnstructor?
• What are the scopes of a variable in java?
• What are the different access modifiers?
• What are the different control statements and how are they different?
• How do you create an array in java?
• What are varargs?
• What are packages and imports?
• What is a static import?
• What is static?
• What are Strings?
• What are some string methods?
• What is the difference between String, StringBuilder, and StringBuffer?
• What is the String Pool?
• What is the difference between the stack and the heap?
• What is an exception?
• What is the difference between exception and error?
• What are the ways one can handle an exception?
• What are checked exceptions and unchecked exceptions?
• How many catch blocks can be used in a try catch?
• What does the finally block do?
• How do I create a custom exception?
• What is autoboxing?
• What is a wrapper class?
• What is garbage collection?
• How do I perform garbage collection?
• what is the difference between final, finally, and finalize?
• What is the reflection API?
• What are the pillars of object oriented programming?
• What is the different between an abstract class and an interface?
• What is transient? Volatile?
• What are the differences between FileinputeStream, FileReader, and bufferedReader (and their output counterparts)?
• What is Scanner?
• What is serializaiton?
• How do I serialize an object?
• What is a marker interface?
• How do I prevent some data from getting serialized?
• What is the difference between Collection and Collections
• What are the various input/delete/get methods for List, Set, and Queue?
• What is an iterator?
• What are generics? Why use them?
• What is the diffence between Comparator and Comparable?
• What is the purpose of the Object class?
• What is the difference between == and .equals?
• What is the purpose of hashcode?
• What is the difference between HashMap and Hashtable?
• How does one iterate through a HashMap?
• What is multithreading and why do we use it?
• What are the different ways to create a thread, what is different about them?
• What are the JVM recognized states of a thread?
• What are various methods that threads have?
• What is synchronization?
• What are the risks of synchronization?
• What is deadlock, livelock and thread starvation? (Consumer/Producer)
• What is JUnit?
• What are the annotations of JUnit?
• What are the different assert methods of JUnit?
• How do I create a test case and test suite in JUnit?
• What is Maven?
• what is the maven lifecycle?
• What is the purpose of the pom.xml?
• What are the purposes of a maven repository among projects?
• What is the difference between Singleton and Factory?
• What is the difference between implicit and explicit casting?