How does Java expression language resolve boolean attributes? (in JSF 1.2)

Basically what you've stated is all there is to it. EL expects the object to follow regular java bean standards. These 2 should help:

• http://docstore.mik.ua/orelly/java-ent/jnut/ch06_02.htm
• http://docs.oracle.com/javaee/1.4/tutorial/doc/JSPIntro7.html#wp71019

It's authoritatively documented in both the JavaBeans Spec and EL Specification.

To take the boolean property as an example, it's described in chapter 8.3.2 of JavaBeans spec:

8.3.2 Boolean properties

In addition, for boolean properties, we allow a getter method to match the pattern:

public boolean is<PropertyName>();

This “is<PropertyName>” method may be provided instead of a “get<PropertyName>” method, or it may be provided in addition to a “get<PropertyName>” method.

In either case, if the “is<PropertyName>” method is present for a boolean property then we will use the “is<PropertyName>” method to read the property value.

An example boolean property might be:

    public boolean isMarsupial();
    public void setMarsupial(boolean m);

So, #{bean.marsupial} expects exactly the above getter/setter pair.

And in chapter 1.23.5 of EL spec:

1.23.5 Coerce A to Boolean or boolean

• If A is null and the target type is not the primitive type boolean, return null
• If A is null or "", return false
• Otherwise, if A is a Boolean, return A
• Otherwise, if A is a String, and Boolean.valueOf(A) does not throw an exception, return it
• Otherwise, error

See also:

• javax.el.PropertyNotFoundException: Property 'foo' not readable on type java.lang.Boolean
• Java: how to name boolean properties