Is a line in a Java program the same thing as a statement?

StackOverflow https://stackoverflow.com/questions/7463098

  •  22-01-2021
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Question

I'm a Java noob. I've only used it for a few days and I'm still trying to figure it all out. In a program, is a line the same thing as a statement?

Was it helpful?

Solution

No. The Java compiler doesn't look at lines, spacing, or other formatting issues when compiling a program. It just wants to see the ; at the end of each statement. This line would work just fine:

int i = 13; i += 23;

However, doing things like this can--and most likely will--cause readability issues with the source code. For this reason, it isn't recommended.

It is also possible for a single statement to span multiple lines:

int i =
    13;

OTHER TIPS

No. I can write:

int x = 1; int y = 2;

That's one line, and two statements.

In a program, is a line the same thing as a statement?

No.

Want to know the difference? Start with the JLS §14.5: Blocks and Statements:

Statement:
        StatementWithoutTrailingSubstatement
        LabeledStatement
        IfThenStatement
        IfThenElseStatement
        WhileStatement
        ForStatement

StatementWithoutTrailingSubstatement:
        Block
        EmptyStatement
        ExpressionStatement
        AssertStatement
        SwitchStatement
        DoStatement
        BreakStatement
        ContinueStatement
        ReturnStatement
        SynchronizedStatement
        ThrowStatement
        TryStatement

StatementNoShortIf:
        StatementWithoutTrailingSubstatement
        LabeledStatementNoShortIf
        IfThenElseStatementNoShortIf
        WhileStatementNoShortIf
        ForStatementNoShortIf

According to Java grammar:

Statement:
    Block
    if ParExpression Statement [else Statement]
    for ( ForInitOpt   ;   [Expression]   ;   ForUpdateOpt ) Statement
    while ParExpression Statement
    do Statement while ParExpression   ; 
    try Block ( Catches | [Catches] finally Block )
    switch ParExpression { SwitchBlockStatementGroups }
    synchronized ParExpression Block
    return [Expression] ; 
    throw Expression   ; 
    break [Identifier]
    continue [Identifier]
    ; 
    ExpressionStatement
    Identifier   :   Statement

Based on this you can easily see that one statement can span multiple lines but also single line can host multiple statements. Also note that statement is a very broad term.

This line includes two statements:

j = 5; j += 3;

So, a line is not necessarily a statement...

Only by common practice, and for readability. In Java statements are terminated with semicolons, or in the case of blocks, by pairs of curlybraces ( { } ).

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