Final answer:
The legal Java identifier among the provided options is oneForAll, as it adheres to the rules for Java identifiers by starting with a letter and containing only letter characters.
Step-by-step explanation:
The question is about Java identifiers, which are the names in a program that are used for classes, methods, variables, and other entities. In Java, a valid identifier must start with a letter (A-Z or a-z), currency character (such as $), or an underscore (_). It cannot start with a number, and after the first character, it can contain any combination of letters, digits, currency characters, or underscores. It must also not be any of the Java reserved words.
Given the options, B) oneForAll is a legal Java identifier because it starts with a letter and contains only letters. The other options either start with a digit or contain illegal characters such as slashes. Therefore:
- A) 1ForAll is not legal because it starts with a number.
- B) oneForAll is legal and the correct answer.
- C) one/4/all is not legal because it contains a slash, which is not allowed.
- D) 1_4_all is not legal because it starts with a number.