Java Developer

Description:
You are given an array of integers. A peak element is an element that is strictly greater than its immediate neighbors. For boundary elements (the first and last elements), only one neighbor needs to be considered. Your task is to write a function that finds and returns any one peak element from the array.

Constraints:

The array contains at least one element.

Example:

Input: [1, 3, 20, 4, 1, 0]

Output: 20

Explanation: 20 is greater than both 3 and 4, so it is considered a peak element.

Identify and explain the differences between many-to-one and many-to-many relationships in relational databases, and describe how they are represented in database schema design.

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Explain how to design an entity class in a Spring Boot application. Describe the key components involved, including commonly used JPA annotations (such as @Entity, @Table, @Id, @GeneratedValue, @Column), how the entity maps to a database table, and best practices to follow when defining entity classes (e.g., using proper data types, meaningful class and field names, avoiding business logic inside entities, and implementing Serializable when needed).

Explain what a functional interface is in Java, including its characteristics (an interface with exactly one abstract method). Describe how lambda expressions can be used with functional interfaces to provide a clear and concise way of implementing the abstract method, thereby reducing boilerplate code compared to traditional anonymous classes.

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Explain the concept of polymorphism in object-oriented programming, where the same interface or method can represent different underlying forms (data types or implementations). Describe the two main types of polymorphism: compile-time (method overloading) and runtime (method overriding), highlighting that runtime polymorphism commonly arises from inheritance. Provide relevant examples to illustrate how polymorphism enhances code flexibility, reusability, and maintainability.