Upgrade to Pro — share decks privately, control downloads, hide ads and more …

Who's Who in Java

Sponsored · Ship Features Fearlessly Turn features on and off without deploys. Used by thousands of Ruby developers.

Who's Who in Java

2023.08.26 むきむきJava 発表資料

Avatar for Yuichi.Sakuraba

Yuichi.Sakuraba

August 27, 2023
Tweet

More Decks by Yuichi.Sakuraba

Other Decks in Technology

Transcript

  1. &MWJT-JWFT public class Elvis { public static final Elvis INSTANCE

    = new Elvis(); private final int beltSize; private static final int CURRENT_YEAR = Year.now().getValue(); private Elvis () { beltSize = CURRENT_YEAR - 1930; } public int beltSize() { return beltSize; } public static void main(String... args) { System.out.println("Elvis wears size " + INSTANCE.beltSize() + " belt."); } } 1) Elvis wears size 0 belt. 2) Elvis wears size -1930 belt. 3) Elvis wears size 93 belt. 4) Null Pointer Exception
  2. &MWJT-JWFT public class Elvis { public static final Elvis INSTANCE

    = new Elvis(); private final int beltSize; private static final int CURRENT_YEAR = Year.now().getValue(); private Elvis () { beltSize = CURRENT_YEAR - 1930; } public int beltSize() { return beltSize; } public static void main(String... args) { System.out.println("Elvis wears size " + INSTANCE.beltSize() + " belt."); } } 1) Elvis wears size 0 belt. 2) Elvis wears size -1930 belt. 3) Elvis wears size 93 belt. 4) Null Pointer Exception