Java Intro Examples

from

• w3schools
• dev.java

Main (Garage)

javac -cp "./w3schools;./w3schools/garage/mypackage" -d "./build/w3schools" Main.java
java -cp "./build/w3schools" Main

1. Asks for data:
   • number of spots
   • person name
   • car brand, color
   • garage spot
2. Prints inputs

Used: ArrayList, inheritance, abstract class, Scanner, loop, for .. in

Classes:

• Main
• Person
• Vehicle
• Car
• GarageSpot
• Garage
• Time
• mypackage

• Main
  • imports local package
  • use Scanner for input
  • use
• Car extends abstract class Vehicle
  • brand
  • color
• Person
  • name
• GarageSpot
  • car: Car
  • owner: _Person
  • spotNumber
• Garage: array of GarageSpot's
• Time
  • imports
    • java.time.LocalDateTime
    • java.time.format.DateTimeFormatter
  • returns formatted now() string

File Handling

javac -d "./build/w3schools/fileHandling" "./w3schools/FileHandling.java"
java -cp "./build/w3schools/fileHandling" FileHandling

• Creates a file
• Writes to the file
• Reads from the file
• Gets file info
• Deletes the file

imports:

• java.io.File
• java.io.FileWriter
• java.io.IOException
• java.util.Scanner

Goods

javac -d "./build/w3schools/goods" "./w3schools/Goods.java"
java -cp "./build/w3schools/goods" Goods

• Creates a HashSet
• Add items to the HashSet
• Removes an item
• Iterates through the HashSet and removes an item with an iterator

imports:

• java.util.Iterator
• java.util.HashSet

Numbers

javac -d "./build/w3schools/numbers" "./w3schools/Numbers.java"
java -cp "./build/w3schools/numbers" Numbers

• Asks for the array size
• Gets the array items with Scanner(System.in)
• Sorts the array with Collections.sort
• Prints original and sorted array with a static method

imports:

• java.util.Scanner
• java.util.ArrayList
• java.util.Collections
• java.util.function.Consumer

PrintFormatted

javac -d "./build/w3schools/printFormatted" "./w3schools/PrintFormatted.java"
java -cp "./build/w3schools/printFormatted" PrintFormatted

Use lamda for a string transformation and output

StringSearch

javac StringSearch.java
java StringSearch

User a regular expression for string search