Hibernate ORM & Unix System Programming Quiz

In Java and C++, the statement 'float abc = 2;' compiles without errors because the integer literal 2 is implicitly converted (widened) to float 2.0. This is a valid implicit type conversion where a smaller type (int) is assigned to a larger type (float).

Unlike fork(), which duplicates the parent process and runs both concurrently, vfork() suspends the parent process until the child process either calls exec() or exits, preventing address space corruption.

Unlike fork(), which duplicates the parent process and runs both concurrently, vfork() suspends the parent process until the child process either calls exec() or exits, preventing address space corruption.

getenv() retrieves environment variable values, while putenv() sets or modifies them. These are standard C library functions for environment variable manipulation. Options A uses setenv() which also exists but the question asks for the standard pair.

usleep() accepts microseconds, enabling sub-second sleep intervals. Standard sleep() only accepts whole seconds. Options like sleep(1/10) would evaluate to sleep(0) in integer arithmetic.

popen() creates a pipe and forks a process, enabling communication between parent and child via the pipe. fork() creates a child process but doesn't establish communication. exec() replaces the current process. open() is for file operations.

Hibernate requires choosing one inheritance strategy per hierarchy. You cannot mix table-per-class (union subclass) and table-per-subclass (joined subclass) within the same hierarchy. Each persistent hierarchy must use a single strategy.

session.contains() checks if an instance exists in the session cache (first-level cache), not whether it's in the database. An entity can be in session cache without being persisted, or exist in database without being in cache.

Zombie processes are children that have terminated but still occupy process table entries. wait() (or waitpid()) is called by parent to reap them, removing the zombie. ps() only lists processes, it doesn't clean zombies.

createQuery().scroll() returns ScrollableResult, not ResultSet types. ScrollableResult allows cursor-like navigation over large result sets without loading everything into memory. ListResultSet is not a Hibernate interface.

Hibernate mapping files can be configured both programmatically via Configuration.addMapping() and declaratively via hibernate.cfg.xml using elements. Both methods are valid and commonly used depending on the setup preference.

SessionFactory is associated with the second-level cache in Hibernate. The first-level cache is at the Session level and is enabled by default, while the second-level cache is at the SessionFactory level and is optional.

In Hibernate, the SessionFactory is responsible for managing the second-level (2nd) cache, which is shared across all sessions. The Session object manages the first-level (1st) cache, which is transaction-scoped.

When hibernate.cache.use_query_cache is set to true, Hibernate enables two cache regions: StandardQueryCache (for caching query results) and UpdateTimestampsCache (for tracking when tables were last modified). This allows efficient query result caching while maintaining data consistency.

When hibernate.cache.use_query_cache is set to true, Hibernate enables two cache regions: StandardQueryCache (for caching query results) and UpdateTimestampsCache (for tracking when tables were last modified). This allows efficient query result caching while maintaining data consistency.

Batch fetching in Hibernate is specifically useful when lazy loading is enabled (lazy="true"). It allows Hibernate to load multiple lazy associations in batches rather than one at a time, reducing the number of database queries and improving performance.

Batch fetching in Hibernate is specifically useful when lazy loading is enabled (lazy="true"). It allows Hibernate to load multiple lazy associations in batches rather than one at a time, reducing the number of database queries and improving performance.

In Hibernate, lazy loading is enabled by default (lazy=true) for associations and collections to optimize performance by avoiding loading related entities until they are explicitly accessed.

HQL (Hibernate Query Language) is used through session.createQuery() method. The session.createCriteria() method is for Criteria queries (deprecated in Hibernate 5+), session.createSQLQuery() is for native SQL queries, and session.load() is a retrieval method, not a query creation method.

In Hibernate, session.load() returns a proxy object immediately without hitting the database. When you attempt to access a property on this proxy, if no matching row exists, it throws an unrecoverable ObjectNotFoundException.