The Transformer model, by design, does not take into consideration the position or order of inputs. This is due to its self-attention mechanism, which considers all inputs as a 'set', ignoring their sequence.

The positional embeddings are added to give the model a sense of order or sequence of the inputs. They provide additional information regarding the position of each word in a sequence. Without positional embeddings, a Transformer model cannot differentiate the order of words, which is crucial in many tasks like natural language understanding.

So in essence, positional embeddings are not a limitation of the Transformer model, but rather a deliberate design choice for handling sequential inputs in tasks where order is important.

Java and JavaScript, despite the similarity in their names, are quite different.

Java is a statically typed, class-based, object-oriented programming language that is designed to run with minimal dependencies across a wide range of computing platforms. It is typically used for large-scale enterprise applications, Android apps, and server-side scripting.

JavaScript, on the other hand, is a dynamically typed, prototype-based, scripting language primarily used for enhancing interactivity and providing rich web content on the client-side. This includes activities such as form submission/validation, interactivity like sliders/carousels, games, and fetching/updating content dynamically.

Key differences:
1. Typing: Java uses static typing (types checked before run-time) where JavaScript uses dynamic typing (types checked at run-time).
2. Running Environment: Java needs the Java Runtime Environment (JRE) to run, whereas JavaScript runs in the web browser.
3. Syntax: Java's syntax is influenced by C/C++, it uses classes and objects heavily. JavaScript's syntax is closer to C, and it uses prototypes instead of classes for inheritance.
4. Use Cases: Java is commonly used for building enterprise-scale applications, while JavaScript is used for scripting on websites and web applications.

Remember, despite their names, they are not related languages but meant for entirely different purposes.

You can convert an array to a List in Java using the Arrays utility class that comes with Java. One of its static methods, `asList()`, does exactly this. Here's how you can do it:

```java
Integer[] array = {1, 2, 3, 4, 5};
List list = Arrays.asList(array);
```
However, there's a caveat. This method returns a fixed-size List backed by the specified array. This means you can't add or remove elements from this list. If you need a modifiable List, you should create a new List object:

```java
Integer[] array = {1, 2, 3, 4, 5};
List list = new ArrayList(Arrays.asList(array));
```
Here, `new ArrayList()` creates a new ArrayList that's initialized with the elements of the array.

If you are using Java 8 or above, you can use a Stream to convert a primitive array into a List:

```java
int[] array = {1, 2, 3, 4, 5};
List list = Arrays.stream(array).boxed().collect(Collectors.toList());
```
`Arrays.stream(array)` returns a Stream containing your array elements, `boxed()` wraps the int values with their equivalent Integer objects, and `collect()` collects them into a List. This returned List is normal and not backed by the array, so you can add or remove elements.

Remember, the `Arrays.asList()` approach doesn't work with primitive arrays like `int[]`, `char[]` etc., because Java treats them as a single object rather than an array of objects, while both `ArrayList(Arrays.asList(array))` and `Stream` approaches work only with object arrays not with primitive arrays.

A NullPointerException is thrown in Java when you're trying to use a reference that points to no location in memory or simply has a value of null. Common causes include:

1. **Invoking methods on an object that is null**: If you call a method on an object that is currently null, you'll get a NullPointerException. Make sure your object is properly initialized before calling any methods on it.

Example:
```java
String str = null;
int length = str.length(); // This will throw NullPointerException
```
2. **Accessing or modifying the fields of a null object**: Similar to the previous point, if you try to access or modify fields of a null object, a NullPointerException is thrown.

Example:
```java
YourClass yourObj = null;
yourObj.someField = 5; // This will throw NullPointerException
```
3. **Throwing null yourself**: You can also get a NullPointerException if you throw null yourself in your code.

Example:
```java
throw null; // This will throw NullPointerException
```
4. **Null array**: If you have a null array and you are trying to access its elements, you'll get a NullPointerException.

Example:
```java
int[] arr = null;
int i = arr[0]; // This will throw NullPointerException
```
5. **Calling `java.util.Objects.requireNonNull()`:** If you pass a null argument to `Objects.requireNonNull()`, it throws NullPointerException.

Example:
```java
Objects.requireNonNull(null); // This will throw NullPointerException
```

To fix it, you need to ensure that all objects are properly initialized before you use them. You should also add appropriate null checks in your code where you've identified possible null references.

Remember, null-safety is a significant aspect of writing robust and error-free code. The best way to handle NullPointerException is to prevent them by using good coding practices and proper exception handling.

Reading a large file efficiently in Java is quite a common problem. Here are some steps you can take to improve the efficiency of your code:

**Use a BufferedReader**

`BufferedReader` is the most efficient way of reading text in Java. It buffers characters so as not to access the disk for each byte, significantly reducing the I/O time. Here's an example:

```java
try (BufferedReader br = new BufferedReader(new FileReader("file.txt"))) {
String line;
while ((line = br.readLine()) != null) {
// process line
}
} catch (IOException e) {
// Handle exception
}
```

**Process Data While Reading**

If you're performing heavy computations on each line, it would be better to process them right away rather than storing them in memory and dealing with them later. This would reduce your program’s memory footprint.

**Use a LineIterator**

Apache Commons IO library's `LineIterator` can be a faster alternative. It doesn't load the entire file into memory, making it a good choice for large files. Here's an example:

```java
try (LineIterator it = FileUtils.lineIterator(new File("file.txt"), "UTF-8")) {
while (it.hasNext()) {
String line = it.nextLine();
// process line
}
} catch (IOException e) {
// Handle exception
}
```

**Use java.nio.file API**

From Java 7 onwards, java.nio.file API has been introduced which has methods such as `Files.lines()`. They make use of Streams thus providing a modern and efficient way in terms of memory and speed.

```java
try (Stream lines = Files.lines(Paths.get("file.txt"))) {
lines.forEach(System.out::println);
} catch (IOException e) {
// Handle exception
}
```

Remember always to close your resources (`BufferedReader`, `FileReader`, etc.), preferably using a try with resources statement as shown above. This ensures that the JVM does not leak any resources.

Finally, profile your application to figure out the real bottleneck, it might not be the file reading but something else in your application.

Java Reflection is a powerful feature which allows you to inspect, monitor and manipulate runtime attributes of classes, interfaces, fields and methods. It’s called reflection because it lets you ‘reflect’ the inner workings of a program.

Here are some of its practical uses:

1. **Exploring the Metadata:** Reflection allows us to obtain the names of class members, their modifiers, annotations, and data types. This is particularly useful while creating tools such as debuggers, IDEs, code viewers, and visual representations of code.

2. **Dynamic Loading:** Reflection allows us to dynamically load classes at runtime. This can be used to increase the extensibility of your application. For instance, JDBC drivers are dynamically loaded before use.

3. **Testing Private Methods:** Sometimes, for unit testing purposes, it's needed to access private methods. Using reflection, we can do this, although it's not a good practice.

4. **Manipulating Objects:** Reflection can create and manipulate objects without knowing their type. This is necessary in object serialization, which involves turning objects into a stream of bytes and vice versa.

Here's a small example of reflection where we fetch method names of a class:

```java
import java.lang.reflect.Method;

public class Test {
// create a method
public void myMethod() {
System.out.println("Reflection Example!");
}

public static void main(String args[]) {
try {
// create an object of Test
Test test = new Test();

// create an object of Class using getClass method
Class obj = test.getClass();

// get all methods of the class
Method[] methods = obj.getMethods();

// print method names
for (Method method : methods)
System.out.println("Method Name: " + method.getName());
} catch (Exception e) {
e.printStackTrace();
}
}
}
```
This will output:
```
Method Name: myMethod
Method Name: wait
Method Name: wait
Method Name: wait
Method Name: equals
Method Name: toString
Method Name: hashCode
Method Name: getClass
Method Name: notify
Method Name: notifyAll
```

While reflection provides great power, be aware it presents certain drawbacks. It can breach the security and integrity of classes by manipulating their private members, it may lead to poor performance due to overhead, and it can induce complexity. So, use it sparingly and responsibly.

In Java, exception handling is performed using the try-catch-finally blocks:

```java
try {
// Code that might throw an exception
} catch (ExceptionType1 e) {
// Handle ExceptionType1
} catch (ExceptionType2 e) {
// Handle ExceptionType2
}
finally {
// Optional block, always executed whether an exception arises or not.
}
```

Here, you replace `ExceptionType1` and `ExceptionType2` with the exceptions you want to catch. The order matters: the Virtual Machine starts with the first `catch` block and tries to match the thrown `Exception` type with the type being caught. General `Exception` types should be last.

Here's a handling 'FileNotFoundException':

```java
try {
File file = new File("nonexistentfile.txt");
FileReader fileReader = new FileReader(file);
} catch (java.io.FileNotFoundException e) {
System.out.println("The file does not exist.");
}
```

Best Practices:
1. **Specificity**: Catch only those exceptions that you can actually handle.
2. **Avoid empty catch blocks**: Catching an exception and doing nothing isn't recommended, as it makes debugging difficult.
3. **Use finally for clean-up**: `finally` block should be used for the clean-up code.
4. **Prefer Unchecked Exceptions**: Unchecked exceptions represent conditions that reflect errors in your program's logic and cannot be recovered from at runtime.
5. **Don’t catch the `Exception` class**: Catching `Exception` will also catch any subclasses — effectively defeating the purpose of your specific catch blocks.

Remember, the purpose of exception handling is to maintain the flow of the program and deal with problems in a controlled manner.

The `public static void main` statement in Java is the entry point for any Java application. When you start a Java program, the JVM looks for a method with this exact signature to start running the program. Here's what each component means:

1. `public`: It is an access specifier, which means the method is accessible from anywhere.
2. `static`: It means the method belongs to the class and not an instance of the class, so no object is needed to invoke the method.
3. `void`: It means the method doesn't return anything.
4. `main`: It's the name of the method. The JVM looks for this method to start the execution of the application.
5. `String[] args`: It's the parameter to the main method, representing command-line arguments.

So, in summary, `public static void main` is necessary as it's the entry point for execution in a Java application.

Multithreading in Java is a feature that allows concurrent execution of two or more parts of a program for maximum utilization of CPU. Each part of such a program is called a thread, and they are lightweight sub-processes.

There are two ways to create a thread in Java:
1. By extending the Thread class
2. By implementing the Runnable interface

**Using the Thread class:**

First, create a new class that extends the Thread class, then override the run() method with the code you want to execute in your thread. Finally, create an object of your new class and call start() on it.

```java
class MyThread extends Thread {
public void run() {
// Your code here
}
}
public class Test {
public static void main(String[] args) {
MyThread t1 = new MyThread();
t1.start();
}
}
```

**Using the Runnable interface:**

First, create a new class that implements the Runnable interface and override the run() method. Your thread's code goes inside this method. Then, create an object of your new class and pass it to a Thread object via its constructor and finally, call start().

```java
class MyRunnable implements Runnable {
public void run() {
// Your Code here
}
}
public class Test {
public static void main(String[] args) {
MyRunnable r = new MyRunnable();
Thread t2 = new Thread(r);
t2.start();
}
}
```

Remember, when a new thread is created, the thread is in a new state. When you call start(), the thread transitions to the runnable state. When the thread's run() method execution completes, it transitions to the dead state. This is basically the lifecycle of a thread.

Finally, note that you can't control the precise timing of when each thread runs since it is dependent on the operating system's thread scheduler.

Multithreading is beneficial in terms of responsive user interface, better use of system resources, and simultaneous and parallel processing. However, it can also lead to issues like deadlock, race conditions, and thread interference if not handled carefully.

To connect your Java application to a MySQL database, you can use the JDBC (Java DataBase Connectivity) API.

First, you need to download the JDBC driver for MySQL. You can download it at https://dev.mysql.com/downloads/connector/j/. Once downloaded, add the .jar file to your classpath.

Next, establish a connection to your MySQL database in your Java code. Here is a basic example:

```java
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class Main {
public static void main(String[] argv) {
System.out.println("Connecting to database...");
Connection conn = null;
try {
// JDBC driver name and database URL
String JDBC_DRIVER = "com.mysql.jdbc.Driver";
String DB_URL = "jdbc:mysql://localhost/DBNAME";

// Database credentials
String USER = "username";
String PASS = "password";

// Register JDBC driver
Class.forName(JDBC_DRIVER);

// Open a connection
System.out.println("Connecting to a selected database...");
conn = DriverManager.getConnection(DB_URL, USER, PASS);
System.out.println("Connected database successfully...");

} catch (SQLException se) {
// Handle errors for JDBC
se.printStackTrace();
} catch (Exception e) {
// Handle errors for Class.forName
e.printStackTrace();
} finally {
// Finally block used to close resources
try {
if (conn != null)
conn.close();
} catch (SQLException se) {
se.printStackTrace();
} // End finally try
} // End try
System.out.println("Goodbye!");
}
}
```

In the code above, replace "DBNAME", "username", and "password" with your actual database name, username, and password.

Finally, you use the conn object to create Statement and ResultSet objects, which you can then use to query and retrieve data from your database.

More info can be found here: https://dev.mysql.com/doc/connector-j/8.0/en/connector-j-usagenotes-connect-drivermanager.html

Don't forget to gracefully close the database connection when you're done (with conn.close()) to prevent memory leaks.