Statements
Figure 130. Statements: General syntax 
Statement's body terminated by “;”
{statement};Figure 131. Statement examples: Declaring and assigning variables
- Variable declaration:
int a;- Value assignment:
a = 33;- Combined declaration and assignment:
int a = 33;
Figure 132. Expression vs. statement
- Expression:
a - 4- Statement:
b = a - 4;Notice the trailing “
;”.
Figure 133. Multiple statements per line
a = b + 3; b = a - 4;Discouraged by good coding practices:
-
Poor readability
-
Hampers debugging
Figure 134. Debugging multiple statements per line
Figure 135. Class scope
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Variable being defined on class level.
-
Visible to all methods.
public class X { // Class variable static int i = 3;◀━━━━━━━━━━━━━━━━━━━━━━━━━┓ ┃ public static void main(String[] args) { ┃ System.out.println("main: i=" + i);━━━━━━━┫ someMethod(); ┃ } ┃ public static void someMethod() { ┃ System.out.println("someMethod: i=" + i);━┛ } }
Figure 136. Method local variable scope
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Method scope being delimited by the { ... } block
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A variable's visibility is restricted to its block:
public class X { public static void main(String[] args) { int i = 1; // Visible in current method System.out.println("i=" + i); someMethod(); // Method call } public static void someMethod() { int j = 3; System.out.println("j=" + j); int i = 17; // No conflict with i in main(...) System.out.println("i=" + i); } }
Figure 137. Blocks
public static void main(String[] args) {
double initialAmount = 34;
{ // first block
final double interestRate = 1.2; // 1.2%
System.out.println("Interest:" + initialAmount * interestRate / 100);
}
{ // second block
final double interestRate = 0.8; // 0.8%
System.out.println("Interest:" + initialAmount * interestRate / 100);
}
}
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