Which protocol is typically used to securely send data over the web?
- FTP
- HTTP
- HTTPS
- SMTP
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.
Which of the following is an invalid variable name in Java?
- $myVar
- 123var
- _myVariable
- myVar1
In Java, variable names must start with a letter, underscore (_), or dollar sign ($) 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.
The ________ keyword is used to declare objects that cannot change.
- final
- static
- transient
- volatile
The final keyword in Java is used to declare objects that cannot change after they are initialized. It can be applied to variables, methods, and classes to make them unmodifiable, constant, or not extendable, respectively.
The method replace(oldChar, newChar) belongs to the ________ class in Java.
- Character
- String
- StringBuilder
- StringManipulator
The replace(oldChar, newChar) method in Java belongs to the String class. This method is used to replace all occurrences of oldChar with newChar in a given string. The other classes listed do not have this specific method.
The process of converting a primitive data type to a wrapper class object in Java is known as ________.
- Autoboxing
- Casting
- Parsing
- Unboxing
The process of converting a primitive data type to a wrapper class object in Java is known as "Autoboxing." Autoboxing is the automatic conversion of primitive data types to their corresponding wrapper classes. For example, converting an int to an Integer.
When a class implements Serializable, it should have a static final field named ______.
- classVersion
- serialVersion
- serialVersionUID
- versionID
When a class implements the Serializable interface, it's recommended to have a static final long serialVersionUID field. This field helps ensure that the serialized and deserialized versions of the class are compatible. It's used to verify that the class being deserialized is compatible with the one that was originally serialized. The other options are not standard.
How can you configure the thread names of an ExecutorService for debugging and identification purposes?
- Thread names are automatically derived from the name of the task submitted to the ExecutorService.
- You can change thread names by calling the setName method on the ExecutorService instance after it's created.
- You can set the thread names when creating a new thread pool using the ThreadFactory interface and providing a custom ThreadFactory implementation.
- You cannot configure thread names for threads in an ExecutorService; they are automatically generated by Java.
To configure thread names of an ExecutorService for debugging and identification purposes, you can provide a custom ThreadFactory implementation when creating the thread pool. This allows you to set meaningful names for the threads, making it easier to identify their purpose in logs and debugging. Thread names are not automatically configurable and are typically based on the default naming conventions unless you specify otherwise.
What is the major drawback of Linear Search compared to other searching algorithms?
- Linear Search has a high time complexity.
- Linear Search is not easily implemented.
- Linear Search is not suitable for sorted data.
- Linear Search requires extra memory.
The major drawback of Linear Search is that it is not efficient for searching in large sets of sorted data. Unlike Binary Search or Hashing, which have logarithmic time complexity, Linear Search has a linear time complexity, making it slower for large datasets. It doesn't take advantage of data being sorted. The other options do not accurately represent the primary drawback of Linear Search.
To retrieve the result of a computation from a Future, you use the ________ method.
- acquire()
- fetch()
- get()
- obtain()
In Java, to retrieve the result of a computation from a Future object, you use the get() method. The get() method blocks until the computation is complete and then returns the result. This is a fundamental method when working with concurrent programming and asynchronous tasks.
The method read() of FileReader class returns ________ when the end of the file is reached.
- True
- -1
- 0
- FALSE
The read() method of the FileReader class returns -1 when the end of the file is reached. This indicates that there are no more characters to read from the file.