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Core Jav

jing profile image limjy Updated on ・1 min read

[WORK IN PROGRESS] Summary sheet (for myself) for java stuff


  1. static
  2. primitive types VS wrapper class
  3. pass by reference VS pass by value
  4. Java 8 stuff Optionals Streams
  5. Reactive Java Flux, Mono (VS stream)
  6. assiging object to null read up

  7. JVM
    java virtual machine. allows you to run java program on different OS
    7.1 JVM - heap and stack memory
    7.2 JVM - garbage collection

primitive VS wrapper class

int VS Intger

int something == null // will give error
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uninitialized int will be 0.

if you want int to be null, make it

Integer something == null // Integer (wrapper class) can be null
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  1. == VS ===
  2. sort [1,35,7,8,65] -> [1,35,65,7,8]
  3. localeCompare

Web Dev

  1. CORS
  2. CSRF
  3. 403 VS 404?

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