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Core Java Syntax

Variables, types, control flow, and methods at a glance.

Primitive types

```
int i = 42;
```
whole numbers
```
double d = 3.14;
```
decimals
```
boolean b = true;
```
true / false
```
char c = 'A';
```
one character
```
long / short / byte / float
```
sized variants

Operators

```
+  -  *  /  %
```
arithmetic (% = remainder)
```
==  !=  >  <  >=  <=
```
comparison → boolean
```
&&  ||  !
```
logical and / or / not
```
=  +=  -=  ++  --
```
assignment

Control flow

```
if (x > 0) { … } else { … }
```

switch (day) { case 1 -> "Mon"; default -> "?"; }

```
for (int i = 0; i < n; i++) { … }
```
```
while (cond) { … }
```
```
for (String s : list) { … }
```
for-each

Methods

```
int add(int a, int b) { return a + b; }
```
```
void greet() { … }
```
returns nothing

static int square(int n) { return n * n; }

The program skeleton

public class App {
  public static void main(String[] args) {
    System.out.println("Hello");
  }
}