What file extension do Java source code files use?
Answer.java
Java source files end in .java; after compiling, the output is stored in .class files.
Coding · Facts & stats
Java facts & stats
7 fact-checked facts about the Java programming language, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
In Java, array indexes start at what number?
Answer0
Java arrays are zero-indexed, so the first element is at index 0.
Going deeper
What does JVM stand for?
AnswerJava Virtual Machine
The JVM runs compiled Java programs, which lets the same program work on different operating systems.
How many bits does Java's primitive int type use?
Answer32
A Java int is always 32 bits, with values from about −2.1 billion to 2.1 billion.
What was the Java language originally called during its development?
AnswerOak
The language was first named Oak, reportedly after a tree outside the lead developer's office, before becoming Java.
Expert level
Which Java keyword stops a variable from being reassigned after it has been given a value?
Answerfinal
A final variable can be assigned only once; 'const' is reserved in Java but not actually used.
How many bits does Java's char type use?
Answer16
A Java char is a 16-bit UTF-16 code unit, so it can hold values from 0 to 65,535.
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