mcupak

class MyClass implements MyInterface {

  @Override
  public void abstractMethod() {
    System.out.println("abstract method called");
  }
}

mcupak

interface MyInterface {

  void abstractMethod();

  default void defaultMethod() {
    System.out.println("default method called");
  }

}

mcupak

void readFile(String file) throws IOException {
  BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(file)));

  try (BufferedReader reader2 = reader) {
    String line;
    while ((line = reader2.readLine()) != null) {
      System.out.println(line);
    }
  }
}

mcupak

1+1
int x = 1+1
System.out.println(x)
Thread.sleep(2000)
/vars
/types
/list
/l
/help
Set<String> set = new HashSet<String>()

mcupak

/
1+1
int x = 1+1
System.out.println(x)
Thread.sleep(2000)
/vars
/types
int inc(int x) { return x+1; }
inc(5)
/list

mcupak

1+1
int x = 1+1
System.out.println(x)
Thread.sleep(2000)
/vars
/types
/list
/l
/help
Set<String> set = new HashSet<String>()

mcupak

1+1
int x = 1+1
System.out.println(x)
Thread.sleep(2000)
/vars
/types
/list
/l
/help
Set<String> set = new HashSet<String>()

mcupak

jshell> Optional.of("something").stream().forEach(System.out::println)
something

jshell> Optional.empty().stream().forEach(System.out::println)

mcupak

jshell> Optional.of("something").or(() -> Optional.of("empty"))
$9 ==> Optional[something]

jshell> Optional.empty().or(() -> Optional.of("empty"))
$10 ==> Optional[empty]

mcupak

jshell> Optional.of("something").orElseGet(() -> "empty")
$7 ==> "something"

jshell> Optional.empty().orElseGet(() -> "empty")
$8 ==> "empty"