Is a Java hashmap search really O(1)?

Is a Java hashmap search really O(1)?

java hashmap big-o time-complexity

java

Time complexity of Java's substring()

java substring time-complexity

java

What are the time complexities of various data structures?

java data-structures time-complexity

java

What is the time complexity of a size() call on a LinkedList in Java?

java size linked-list time-complexity

java

Detecting if a string has unique characters: comparing my solution to "Cracking the Coding Interview?"

java string algorithm big-o time-complexity

java

Time complexity of contains(Object o), in an ArrayList of Objects

java arraylist time-complexity

java

Priority Queue remove complexity time

java complexity-theory time-complexity priority-queue

java

Why does this O(n^2) code execute faster than O(n)? [duplicate]

java time-complexity big-o

java