There is no concept similar to pointers in Java. Pointers are a feature in C Programming using which a programmer can access the memory. This was the cause of major catastrophic programming bugs. The creators of Java excluded this feature just to avoid such catastrophic bugs.
Java
programmers are always confused with pointers
A null pointer exception in java comes when you are trying to perform any action on an object that isnt initialized/has a value i.e., is a NULL Value Ex: private String s; //declare a string if(s.equals("test")){ //do something.. } You will get a null pointer in the if condition because you are checking a value that is null which is not allowed..
At any given point of time you cann't get the address of a variables of java program. This is meant for security purpose only.
No. You cannot throw or catch Null pointer exceptions
Java does not have pointers
Java
programmers are always confused with pointers
Becuse there r no use of pointer in java. So we can't think about memory manipulation..............
A null pointer exception in java comes when you are trying to perform any action on an object that isnt initialized/has a value i.e., is a NULL Value Ex: private String s; //declare a string if(s.equals("test")){ //do something.. } You will get a null pointer in the if condition because you are checking a value that is null which is not allowed..
At any given point of time you cann't get the address of a variables of java program. This is meant for security purpose only.
No. You cannot throw or catch Null pointer exceptions
The best way to fix uncaught exception java lang Null Pointer Exception on a Blackberry 8300 is by doing a restart. Shut the phone off and remove the battery for a minute. Replace the battery and turn the phone back on.
java is securejava uses the pointer internally. programer cannot use the pointer in our program explicitly. due to use of pointers information may be lostex-int *p;int a=56;int b=98;p=&a;p=&b;in above program first time pointer points the a value and in next line p points the b value, so here a information is lost
A String is treated as an object, meaning there is an object on the heap. Of course, the variable you define is a pointer to the object, and it is stored on the stack.A String is treated as an object, meaning there is an object on the heap. Of course, the variable you define is a pointer to the object, and it is stored on the stack.A String is treated as an object, meaning there is an object on the heap. Of course, the variable you define is a pointer to the object, and it is stored on the stack.A String is treated as an object, meaning there is an object on the heap. Of course, the variable you define is a pointer to the object, and it is stored on the stack.
The final keyword can be used to modify a class, method, or variable.When used on a variable, it means that variable cannot be changed once set.When used on a method, it means that no subclasses may override that method.
this is treated like a pointer to the object it's written in. It's important if you want to call a method with the object calling it as an argument, or something like that.
I think you're referring to the C/C++ concept of "dangling pointers." This is when you allocate some memory to a pointer, then deallocate that memory, but don't change the pointer. This causes any attempted use of the pointer to return an unused memory address. There is no such concept in Java, since the programmer has little to no control over how memory is allocated or freed. The closest thing I can think of is if you're using a class such as a Reader, in which you can close the object (Reader.close()) and then still have a reference to it. But in this case (and other similar cases) attempting to use the Reader further will result in an IOException being thrown.
On the lower level of Java, a "reference" can be thought of like a pointer in C. It is essentially an integer which refers to (points to) a location in memory where the object data exists. // "button" is a reference to a JButton with a "1" on it (the object). JButton button = new JButton("1");
By reference. The name of the string is converted to a pointer (in C/C++) and given to the function as the address of the first element. (In Java, all objects are passed by reference, and there are no pointers.)
A null pointer exception is thrown when you are trying to manipulate an object that is null. It is just the name and does not have any relevance to the pointers as in C Example: ArrayList lst = null; Object obj = lst.get(0); In the first line we have declared an array list. Without initializing it we have tried to access the element in the 0th position. This would cause a null pointer exception.
1. pointer to a constant means you can not change what the pointer points to 2. constant pointer means you can not change the pointer.
Example: int x; -- integer int *px= &x; -- pointer to integer int **ppx= &px; -- pointer to pointer to integer int ***pppx= &ppx; -- pointer to pointer to pointer to integer
A pointer only holds an address information (location) in the memory. if a pointer holds points another pointer then it is a pointer to an other pointer. Pointer holds an address in the memory so in that address there is an other location information that shows another location.
In JAVA, all variables are reference variables, and there are no pointer variables. Even though the platform may implement them as pointers, they are not available as such. In C, no variables are reference variables. They are a C++ enhancement. In C++ a reference variable is syntactically the same as a pointer variable, except that the use of the indirection operator (*) is implicit. You do declare reference variables slightly differently than pointer variables but, once you do so, they can be treated as non-pointer variables. Reference variables also cannot be redefined once they have been initialized to point to some object. They are const. Structurally, there is no difference between a pointer variable and a reference variable. They are both still pointers. The compiler just makes it easier to treat reference variables and non-pointer variables the same way.