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with:
String s = someMethod(...)
if (s) { ... }
Semicolons
Semicolons are for the most part unnecessary in Groovy, the exception being the tra‐
ditional for loop (although you’ll most likely prefer the semicolon-free Groovy for/in
version). Also, if you want to have multiple statements on one line, you still need to
delimit them with semicolons.
Optional Return
You can omit the return keyword in a method or closure, because Groovy treats the
last expression value as the return value if you don’t use return.
Scope
Scope modifiers are often omitted in Groovy because the default scope is public. You
can still define private or protected fields and methods. Because package scope is the
default in Java and there’s no keyword for that, Groovy added the groovy.trans
form.PackageScope annotation in version 1.8 for classes, methods, and fields.
Parentheses
You can often omit parentheses in method calls. This is only true if the method has
arguments, because otherwise the call would look like property access. So, for example,
all but the last of these are valid:
println("Using parentheses because I can")
println "Omitting parentheses because I can"
println()
println // not valid; looks like property access
// for a nonexistent getPrintln() method
You can’t omit parentheses from the right side of an assignment, however:
int sum = MathUtils.add(2, 2) // ok
int product = MathUtils.multiply 2, 2 // invalid, doesn't compile
Default Imports
Another space saver is the extended list of default imports. Java automatically imports
everything from the java.lang package, and Groovy extends this to include java.io.*,
java.net.*, java.util.*, groovy.lang.*, and groovy.util.*, as well as the
java.math.BigDecimal and java.math.BigInteger classes.
16 | Chapter 1: Introduction to Groovy