Exception in thread "main" java.lang.NullPointerException: Cannot invoke "String.length()" because "mystr" is nullat com.example.myJavaProject.Demo.main(Demo.java:18) In the above code,NullPointerExceptionis thrown as thelength()method is called for anullstring object without performing anynu...
Java 8 is a giant step forward for the Java language. Writing this book has forced me to learn a lot more about it. In Project Lambda, Java gets a new closure syntax, method-references, and default methods on interfaces. It manages to add many of the features of functional languages wit...
Avoiding NullPointerException in Java What are the differences between a HashMap and a Hashtable in Java? How do I generate random integers within a specific range in Java? How can I create a memory leak in Java? What is the difference between public, protected, package-private and ...
NullPointerException is anunchecked exceptionand extends RuntimeException class. Hence there is no compulsion for the programmer to catch it. Is FileNotFoundException checked or unchecked? FileNotFoundException isa checked exception in Java. Anytime, we want to read a file from the filesystem, Ja...
Is Java "pass-by-reference" or "pass-by-value"? How do I read / convert an InputStream into a String in Java? Avoiding NullPointerException in Java What are the differences between a HashMap and a Hashtable in Java? What is the difference between public, protected, package-private...
null is a very critical factor that means we need to focus when we work with null. null is a keyword in Java and it is related to NullPointerException and NullPointerException is a package in java.lang package like this java.lang.NullPointerException. We will see NullPointerException throw...
Constants arebasically variables whose value can't change. In C/C++, the keyword const is used to declare these constant variables. In Java, you use the keyword final . What does const in Java mean? Const (constant) in programming is a keyword that defines a variable or pointer as unchang...
Aggregation_Example agrn; String nameClass; char c; Student(String classWhich,char section,Aggregation_Example address) { this.nameClass=classWhich; this.c=section; this.agrn=address; // you havent used in your example which raised a nullpointer exception...
classMyClass{StringmyAttribute;}MyClassmyObject=null;System.out.println(myObject.myAttribute);#Output:#Exceptionin thread"main"java.lang.NullPointerException Java Copy In the above example, we try to accessmyAttributefrommyObject, which isnull. This results in a Null Pointer Exception. ...
Can I declare a constant pointer in C? Yes, you can declare a constant pointer in C using the const modifier. This means that the pointer itself cannot be modified to point to a different memory location, but the value stored at the memory location it points to can still be changed. ...