If methods modifying static variables are not synchronized, it can result in inconsistent or incorrect values being assigned to those variables. Since multiple threads can access and modify static variables concurrently, without synchronization, they may read and write to the variable at the same time, leading to data corruption or inconsistent state. Proper synchronization is essential to ensure thread safety when working with shared static variables.

In a multi-threaded environment, a race condition can occur when multiple threads access and modify a shared variable concurrently without proper synchronization. Option 1 correctly identifies this scenario. Option 2 refers to context switching but not directly to race conditions. Option 3 is a preventative measure, and Option 4 is a solution to race conditions, not a cause.

The submit(Runnable task) method of the ExecutorService interface is used to submit a task for execution and returns a Future object. This Future can be used to monitor the progress and retrieve the result of the task asynchronously. The other options are not correct methods for submitting tasks to an ExecutorService.

In Java, a class can contain variables, which are used to describe the properties or attributes of objects. Methods are used to define the behaviors of objects. Constructors initialize objects, and interfaces declare methods that must be implemented.

In JavaFX, the TextField class is used to create a single-line text input field. It allows users to enter text or data. The other options, Text, TextInputField, and JText, are not the correct classes for creating text fields in JavaFX.

In Java, the equalsIgnoreCase() method of the String class is used to compare two strings for equality while ignoring differences in case. It returns true if the two strings are equal, regardless of whether the characters are in uppercase or lowercase. The other options, equals(), compareToIgnoreCase(), and compareTo(), do not perform case-insensitive comparisons.

The getConnection method of the java.sql.DriverManager class is used to establish a connection to a database. It takes parameters like the database URL, username, and password to create a connection to the specified database server. It does not close connections, retrieve driver info, or execute SQL queries.

In a multi-threaded environment, StringBuilder is primarily used due to its better performance. Unlike StringBuffer, StringBuilder is not synchronized, which makes it more efficient when thread safety is not a concern. StringBuffer is synchronized and is used when thread safety is required. Using both interchangeably may lead to synchronization overhead.

The HTTPS (Hypertext Transfer Protocol Secure) protocol is typically used to securely send data over the web. It encrypts the data being transmitted, providing confidentiality and integrity. FTP, HTTP, and SMTP are different protocols with their own purposes, but they are not primarily designed for secure data transfer.

In Java, variable names must start with a letter, underscore (_), or dollar sign ($) and may be followed by letters, digits, underscores, or dollar signs. Option 2 (123var) is invalid because it starts with a digit, which is not allowed.