A compilation unit is a Java Source Code file.
Yes, an empty .java file is a perfectly valid source file.
Yes, a .java file contains more than one java class, provided at the most one of them is a public class.
The JVM spec is a blueprint for the JVM generated and owned by Sun Microsystems, now Oracle.
The JVM implementation is the actual implementation of the spec by a vendor.
The JVM Runtime is the actual running instance of a JVM implementation.
BDK (Bean Development Kit) is a tool that enables us to create, configure and connect a set of Beans and be used to test Beans without writing code.
bin contains tools such as javac, applet viewer, awt tool etc., whereas lib contains packages and variables.
Two parts in executing a Java program are:
Java Compiler is used for the compilation of a Java program.
Java Interpreter is used for executing the compiled program
PATH is used for setting up an environment for the operating systems. The operating system will look in this PATH for executables.
CLASSPATH is used for setting up the environment for Java. Java will use the classpath to find compiled classes.
You’ll need to set CLASSPATH and PATH in order to be able to run Java programs.
JavaBeans is a portable, platform-independent component model written in the Java programming language. It enables developers to write reusable components once and run them anywhere-benefiting from the platform-independent power of Java technology. JavaBeans are Java classes which adhere to certain coding conventions:
Must have setter & getters methods.
Must declare a public default constructor.
Implements Serializable interface.
A Bean is a java class that has getter and setter methods without any logic in it. It is used for holding data.
A Java class can have everything a java Bean has as well as some logic inside it.
A bean class can be a POJO class but a POJO can’t be a Java Bean class.
Unicode requires 16 bits and ASCII requires 7 bits. Although the ASCII characters use only 7 bits, it is usually represented as 8 bits. UTF-8 represents characters using 8, 16, and 18-bit patterns. UTF-16 uses 16-bit and larger bit patterns.
A class and the main( ) method declaration is required. The main method tells the application starting point.
Void is the return type of the main method.";"";"Here is a list of one liner Question and Answers which will be helpful in interviews.";"Administrator";"Java";"2020-03-30 00:00:00+00";"''" 32;"Interview Question and Answers Part 3";"
In the Bitwise operator, if the first operator evaluates to true in OR (|) and False in AND (&) then the second expression will also be evaluated. But, in Logical Operator, if the first operand evaluates to true in OR (|) and False in AND (&) then the second expression will not be evaluated.
The >> operator is also called Arithmetic Shift Right which carries a signed bit when shifting right. The >>> operator is also called a logical shift right which does not carry any signed bit.
No, shift operators can be applied only to integer or long types
They are discarded.
In case of signed left shift >> the new bits are set to zero. But in case of signed right shift << it takes the value of most significant bit before the shift that is if the most significant bit before shift is 0 it will introduce 0, else if it is 1, it will introduce 1.
Operators are special symbols used in expressions. The following are the types of operators:
During compilation, the values of each case of a switch statement must evaluate to a value that is an integer or compatible with an integer value.
Yes, for statement can loop indefinitely. Here’s the code: for(;;) ;
A break statement results in the termination of the statement to which it applies (switch, for, do, or while). A continue statement is used to end the current loop iteration and return control to the loop statement.
A while loop checks at the beginning of a loop to see whether the next loop iteration should occur. A do-while statement checks at the end of a loop to see whether the next iteration of a loop should occur. A do loop will always execute at least once.
Variables are locations in memory that can hold values. Before assigning any value to a variable, it must be declared.
Java has three kinds of variables namely:
Instance Variable: Local variables are used inside blocks as counters or in methods as temporary variables and are used to store information needed by a single method.
Local Variable: Instance variables are used to define attributes or the state of a particular object and are used to store information needed by multiple methods in the objects.
Class Variable: Class variables are global to a class and to all the instances of the class and are useful for communicating between different objects of all the same class or keeping track of global states.
A literal represents a value of a certain type. There are different types of literals namely number literals, character literals, boolean literals, string literals, etc.
An array is an object that stores a list of homogeneous datatype elements.
Array variable indicates the type of object that the array holds. Ex:
a, b and d are the correct way of declaring an array.
Static variables are shared by all instances of a class.
Final variable’s value cannot be changed. It becomes a constant.
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