Classes - The Java Language Specification - page 250

A return statement (§ 14.17 ) may be used in the body of a constructor if it does not include
an expression.
Example 8.8.7-1. Constructor Bodies
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class Point {
int x, y;
Point(int x, int y) { this.x = x; this.y = y; }
}
class ColoredPoint extends Point {
static final int WHITE = 0, BLACK = 1;
int color;
ColoredPoint(int x, int y) {
this(x, y, WHITE);
}
ColoredPoint(int x, int y, int color) {
super(x, y);
this.color = color;
}
}
Here, the first constructor of ColoredPoint invokes the second, providing an additional
argument; the second constructor of ColoredPoint invokes the constructor of its super-
class Point , passing along the coordinates.
8.8.7.1. Explicit Constructor Invocations
ExplicitConstructorInvocation:
NonWildTypeArguments opt this ( ArgumentList opt ) ;
NonWildTypeArguments opt super ( ArgumentList opt ) ;
Primary . NonWildTypeArguments opt super ( ArgumentList opt ) ;
NonWildTypeArguments:
< ReferenceTypeList >
ReferenceTypeList:
ReferenceType
ReferenceTypeList , ReferenceType
Explicit constructor invocation statements can be divided into two kinds:
• Alternate constructor invocations begin with the keyword this (possibly prefaced
with explicit type arguments). They are used to invoke an alternate constructor of
the same class.