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Java MCQ: Which method is used to close a JDBC connection? a) terminate() b) close() c) shutdown() d) disconnect() Answer: b) close() Explanation: The close() method is used to close a JDBC connection. This method is called on the Connection object to release the database resources associated with the connection. It is important to close […]

Java MCQ: Which JDBC interface is used for batch updates? a) Statement b) PreparedStatement c) BatchStatement d) BatchUpdate Answer: a) Statement Explanation: The Statement interface in JDBC is used for batch updates. Batch updates allow you to execute multiple SQL statements as a single batch, which can improve performance by reducing the number of database

Java MCQ: Which method is used to rollback a transaction in JDBC? a) undoTransaction() b) rollbackTransaction() c) rollback() d) revert() Answer: c) rollback() Explanation: The rollback() method is used to rollback a transaction in JDBC. When auto-commit mode is disabled, you can use rollback() on the Connection object to undo all changes made in the

Java MCQ: Which JDBC method is used to commit a transaction? a) commitTransaction() b) executeCommit() c) commit() d) finalizeTransaction() Answer: c) commit() Explanation: The commit() method is used to commit a transaction in JDBC. When auto-commit mode is disabled, multiple SQL statements can be grouped into a single transaction. After executing all the statements, calling

Java MCQ: What is the role of the ResultSet interface in JDBC? a) To manage database connections b) To execute SQL queries c) To retrieve and manipulate query results d) To manage SQL transactions Answer: c) To retrieve and manipulate query results Explanation: The ResultSet interface in JDBC is used to retrieve and manipulate the

Java MCQ: Which interface is used to execute SQL queries in JDBC? a) Statement b) ResultSet c) Connection d) PreparedStatement Answer: a) Statement Explanation: The Statement interface is used to execute SQL queries in JDBC. It provides methods to execute SQL statements, such as executeQuery() for SELECT statements, executeUpdate() for INSERT, UPDATE, and DELETE statements,

Java MCQ: Which method is used to establish a connection to a database? a) DriverManager.connect() b) DriverManager.getConnection() c) Connection.create() d) Database.connect() Answer: b) DriverManager.getConnection() Explanation: The DriverManager.getConnection() method is used to establish a connection to a database in JDBC. This method takes a database URL, a username, and a password as arguments and returns a

Java MCQ: Which package contains the JDBC API? a) java.sql b) javax.jdbc c) java.database d) javax.sql Answer: a) java.sql Explanation: The java.sql package contains the JDBC API. This package provides the necessary classes and interfaces for connecting to databases, executing SQL queries, and processing the results. Some of the key classes and interfaces in java.sql

Java MCQ: What does JDBC stand for? a) Java Data Connection b) Java Database Connectivity c) Java DataBase Compiler d) Java Data Component Answer: b) Java Database Connectivity Explanation: JDBC stands for Java Database Connectivity. It is an API in Java that allows developers to connect to and interact with databases from Java applications. JDBC

Java MCQ: How does the Files.writeString() method introduced in Java 11 work? a) It appends a string to an existing file b) It writes a string to a file, overwriting any existing content c) It writes a byte array to a file d) It creates a new directory with the given string as the name

Java MCQ: What does the Files.readString() method in Java 11 return? a) A List of strings b) A byte array c) A single string containing the file’s content d) A Stream of strings Answer: c) A single string containing the file’s content Explanation: The Files.readString() method, introduced in Java 11, reads the content of a

Java MCQ: Which of the following is a new method added to the String class in Java 11? a) trim() b) strip() c) substring() d) replace() Answer: b) strip() Explanation: The strip() method is one of the new methods added to the String class in Java 11. This method removes all leading and trailing whitespace

Java MCQ: How does the sendAsync() method in Java 11 HttpClient differ from the send() method? a) It sends requests over a different protocol b) It sends requests asynchronously, returning a CompletableFuture c) It sends requests faster d) It sends requests in batches Answer: b) It sends requests asynchronously, returning a CompletableFuture Explanation: The sendAsync()

Java MCQ: What is the return type of the send() method in the Java 11 HttpClient class? a) HttpResponse b) String c) Future d) void Answer: a) HttpResponse Explanation: The send() method in the Java 11 HttpClient class returns an instance of HttpResponse. This method is used to send an HTTP request synchronously, meaning that

Java MCQ: Which method is used to create a new instance of HttpClient in Java 11? a) HttpClient.create() b) HttpClient.newBuilder() c) HttpClient.newHttpClient() d) HttpClient.getInstance() Answer: c) HttpClient.newHttpClient() Explanation: The HttpClient.newHttpClient() method is used to create a new instance of HttpClient in Java 11. This method returns a default HttpClient that can be used to send

Java MCQ: What is the primary use of the Java HTTP Client introduced in Java 11? a) To create TCP connections b) To send and receive HTTP requests and responses c) To manage WebSocket connections d) To encrypt data over a network Answer: b) To send and receive HTTP requests and responses Explanation: The primary

Java MCQ: What does the Local-Variable Syntax for Lambda Parameters in Java 11 allow you to do? a) Define local variables in lambda expressions b) Use the var keyword to declare the types of lambda parameters c) Use instance variables inside lambda expressions d) Automatically infer the types of lambda parameters Answer: b) Use the

Java MCQ: What does the Optional.orElseThrow() method introduced in Java 10 do? a) Returns the contained value if present, otherwise throws NoSuchElementException b) Returns the contained value if present, otherwise returns null c) Returns the contained value if present, otherwise returns a default value d) Returns the contained value if present, otherwise throws IllegalStateException Answer:

Java MCQ: How does the Collectors.toUnmodifiableMap() method handle duplicate keys in Java 10? a) It merges the values associated with duplicate keys b) It throws an IllegalStateException c) It ignores duplicate keys d) It keeps only the first occurrence of the key Answer: b) It throws an IllegalStateException Explanation: The Collectors.toUnmodifiableMap() method, introduced in Java

Java MCQ: What is the purpose of Collectors.toUnmodifiableSet() introduced in Java 10? a) To create a mutable set from a stream b) To create an unmodifiable set from a stream c) To create a sorted set from a stream d) To create a set that allows duplicate elements Answer: b) To create an unmodifiable set

Java MCQ: Which Java 10 feature allows you to collect elements into an unmodifiable list using Collectors? a) Collectors.toUnmodifiableSet() b) Collectors.toUnmodifiableMap() c) Collectors.toUnmodifiableList() d) Collectors.toImmutableList() Answer: c) Collectors.toUnmodifiableList() Explanation: The Collectors.toUnmodifiableList() method, introduced in Java 10, allows you to collect elements into an unmodifiable list. This method is part of the java.util.stream.Collectors class and is

Java MCQ: What is the behavior of the Map.copyOf() method introduced in Java 10 when invoked with a map containing null keys or values? a) It removes the null keys or values from the map b) It replaces null keys or values with empty strings c) It throws a NullPointerException d) It converts null keys

Java MCQ: How does the Set.copyOf() method introduced in Java 10 behave when given a null argument? a) It returns an empty set b) It throws a NullPointerException c) It creates a set with a null element d) It ignores the null argument Answer: b) It throws a NullPointerException Explanation: The Set.copyOf() method, introduced in

Java MCQ: What does the List.copyOf() method introduced in Java 10 return? a) A deep copy of the list b) A shallow copy of the list c) An unmodifiable copy of the list d) A mutable copy of the list Answer: c) An unmodifiable copy of the list Explanation: The List.copyOf() method, introduced in Java

Java MCQ: What is the primary purpose of the var keyword introduced in Java 10? a) To declare a constant variable b) To infer the type of a local variable at compile-time c) To create immutable objects d) To define global variables Answer: b) To infer the type of a local variable at compile-time Explanation: