"verify" is not a Java keyword. I believe the link, in related links, has the complete list of Java keywords.
No, 'check' is not a keyword in java language.
yes, float is keyword and data type in java
There is no "foreign" keyword in Java, however, there is a native keyword that declares native methods in a native language, such as C or C++.For full list of keywords in Java see related question.
Literal in java are L, F, null, true, false These act as keyword(have special meaning in java) but these does'nt comes under the category of Java Keyword.
"int" is the keyword for integer
That is used to verify whether an object is based on the specified class (or a subclass).
In Java, the final keyword specifies that the object created cannot be further redefined or derived.
sizeof is not a keyword in Java but many classes have size() or length() methods, which can mean the number of elements, characters, etc. depending on the class.
"this" is a Java keyword that references the current object. Any part of the object(instance variables, methods, constructors) can be accessed by calling this.[member].
new is a keyword to create a instance of object any class.
we do it using the throw keyword.
No extern keyword in Java.