Interface is 100% abstract ..
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True
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False
An interface in Java is 100% abstract - it can only contain abstract method declarations (and constants). Unlike abstract classes which can have both abstract and concrete methods, interfaces cannot have any implemented methods. This is the fundamental definition of an interface in Java - it provides a contract without implementation.
In traditional object-oriented programming (and classic Java, pre-Java 8), an interface is indeed 100% abstract: it declares method signatures without providing any implementation, and any class implementing the interface must supply the actual method bodies. This makes the statement "True" in the classical sense typically tested in OOP/Java fundamentals courses. Note that since Java 8, interfaces can include "default" and "static" methods with concrete implementations, which technically breaks the "100% abstract" rule in modern Java — but exam questions phrased this generically almost always intend the classical, pre-default-methods definition of an interface as purely abstract, which is what's being tested here.