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Java is a popular, versatile, and widely-used programming language that is object-oriented. Its structure allows programmers to write reusable code and makes the process of developing complex applications easier. Java's syntax is similar to that of C++ but with fewer low-level facilities. One key feature of Java is its platform independence.
Thanks to the Java Virtual Machine (JVM), Java code can run on any device that has a JVM, without needing recompilation. This ability is often summarized by the phrase "write once, run anywhere." Java's extensive standard library provides a range of tools for developers, including utilities for input/output operations, networking, data structures, and more.

• Java programs are structured in classes and methods.
• The `main` method is the entry point of any Java application.
• Java has robust exception handling mechanisms.

These features, among others, make Java an ideal choice for developing secure, portable, and high-performance applications across various domains.

Methods in Java are blocks of code that perform a specific task and can be called upon with a method name. They help break down complex problems into smaller, more manageable pieces. Implementing a method involves defining its signature, which includes its access modifiers, return type, method name, and parameters.
For example, to implement the `minimum3` method:

• Use the `public static` access modifiers.
• The return type should be `double` if working with floating-point numbers.
• Receive three parameters as input, which can be named `num1`, `num2`, and `num3`.

The `minimum3` method specifically utilizes the `Math.min` function to determine the smallest value among three floating-point numbers by comparing the first two numbers and then the result with the third number.
Careful method implementation improves code modularity, clarity, and reusability.

Java provides various ways to handle user input, the most common being the `Scanner` class. This class allows programmers to read input from various sources, including the console. It is an essential tool for making interactive programs. The `Scanner` object is created with a reference to `System.in` to read user input from the standard input stream.
To handle user input in the application:

• Instantiate a `Scanner` object at the start of the program.
• Use methods like `nextDouble()` to read floating-point numbers.
• Always remember to handle potential exceptions, such as `InputMismatchException`, which occurs when the input does not match the expected type.

After processing the input, it's crucial to close the `Scanner` object with `close()` to free up resources. Handling user input correctly is vital for ensuring that applications can accommodate various input scenarios without failure.

Floating-point numbers in Java represent fractional numbers and are used for precise calculations. They are defined using either the `float` or `double` keyword, with `double` being the default and more commonly used type due to higher precision.
Java's `double` data type supports approximately 15 decimal digits of precision, making it suitable for scientific calculations. It's important to understand that floating-point arithmetic can introduce rounding errors. As such, developers must be cautious when comparing floating-point numbers due to potential precision issues.

• Declare floating-point numbers with the `double` keyword for better precision.
• Be aware that `Math.min()` functions with `double` values return the smallest of the arguments while considering precision limits.
• Use formatting options like `DecimalFormat` if specific decimal precision display is needed.

By knowing how to handle floating-point numbers, developers can create reliable applications that handle real-number computations efficiently.