java.util.Objects #

Method	Description
`equals(Object a, Object b)`	Safely compares two objects for equality.
`deepEquals(Object a, Object b)`	Performs a deep comparison of two objects, including arrays.
`hash(Object... values)`	Generates a hash code for multiple objects.
`hashCode(Object o)`	Returns the hash code of an object or `0` if `null`.
`toString(Object o)`	Returns the `toString()` of an object or `"null"`.
`toString(Object o, String nullDefault)`	Returns the `toString()` of an object or a default string.
`requireNonNull(T obj)`	Throws `NullPointerException` if the object is `null`.
`requireNonNullElse(T obj, T defaultObj)`	Returns the object if non-`null`, or a default value.
`isNull(Object obj)`	Checks if an object is `null`.
`nonNull(Object obj)`	Checks if an object is non-`null`.
`compare(T a, T b, Comparator<? super T> c)`	Compares two objects using a comparator.
`checkIndex(int index, int length)`	Ensures that the index is within valid bounds.

Exceptions #

Exception	Type	Description
`NullPointerException`	Unchecked	Attempt to use `null` as if it were an object.
`ArrayIndexOutOfBoundsException`	Unchecked	Accessing an array with an illegal index.
`IllegalArgumentException`	Unchecked	Method argument is inappropriate or illegal.
`IllegalStateException`	Unchecked	Method called at an inappropriate time.
`IndexOutOfBoundsException`	Unchecked	General index is out of range.
`ArithmeticException`	Unchecked	Arithmetic error (e.g., divide by zero).
`ClassCastException`	Unchecked	Invalid casting of an object.
`NumberFormatException`	Unchecked	Failure to convert string to a number.
`IOException`	Checked	I/O operation failure.
`FileNotFoundException`	Checked	File operation on a file that doesn’t exist.
`InterruptedException`	Checked	Thread is interrupted while it is waiting or sleeping.
`SQLException`	Checked	Database access or SQL error.
`NoSuchElementException`	Unchecked	Attempting to access an element that does not exist.
`UnsupportedOperationException`	Unchecked	Operation is unsupported.
`TimeoutException`	Checked	Operation times out.
`OutOfMemoryError`	Error	JVM runs out of memory (serious issue).