I have a checksum function that is suppose to read IPV4 packet and return a short integer value. The IPV4 packets are stored in a byte array. I am having trouble storing the first 8 bits and second 8 bits of the short integer into the byte arrays especially when they have leading 1s. For example, if my checksum returns 5571 (binary = 0001 0101 1100 0011) The first 8 bits is suppose to represent 195 but when I try to assign a larger integer type to a btye the information gets sign extended. The 195 turns into -61. I tried using bit addition like array[10] = array[10] & 0xff, but the result remains the same.
public static short checksum(byte [] a, int length) {
short sum = 0;
long data;
int i = 0;
while(length > 1) {
data = (((a[i] << 8) & 0xff00) | ((a[i + 1]) & 0xff));
sum += data;
i know that int [][] x = new int[2][2] will generate a 2x2 array but I'm looking at a certification mock question and I see double [][] da = new double [3][]. What is the empty [] on the right hand side of the equal sign trying to tell me? Is there some default value?
I am new to Android. I have byte array of size 10. I am passing the Decimal values (131 - 140) to byte array. But while printing I get Negative (-) values with decreasing order .
How can I get same value as positive values?
Or How can I store positive value e.g. 131 as byte array element.
Please not my requirement is array must be ByteArray only
I and a friend are working with a project to create a file system, who manages a secondary memory simulated as a byte array in Java. We want the file system to be a hierarchical tree structure like in UNIX.
We have come quite far, but the paths are not handled correct. I seem to have mistaken the relative folder ./ for the root folder, but it should mean "working directory folder", ie, where I stand now. That is, if I stand in /dir1 as my "working directory" and make mkdir ./dir2 then should dir2 end up as subfolder in dir1. But with me it appears in the root.
There's a site that uses DBsign UWS to validate personal certificates on a smart card. I wound up breaking that functionality by moving the default Java truststore so I could create a new one with just root/intermediate CAs that I trust (I have no desire to allow apps signed in China, Russia, Turkey, and countries spelled with heiroglyphs). Now, my browser believes the UWS is self-signed and rfuses to run it. I need to find the certificate used to sign that app to see which cert(s) signed it, so I can add them back to the truststore. How can I find that?
import javax.swing.*; import java.awt.MenuBar; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; public class NewCalculator implements ActionListener { //assign button clicked number and answer onto variables.
[Code] .....
Also what is the code I need to use to do the percentage and square root calculation in the calculation. Cos I am not sure about the sign I am required to use to do the calculation.
The if statement is where the code to make the clear button (C and CE) work.
1) when you create a class and compile it and open and see the class using javap command .. that class file contains that it extends java.lang.object and a default constructor is created automatically..... But when you extends another class the java.lang.Object class is not appeared as extended why?
Code example:
1St Case ----- Java code:
public class temp(){ }
Javap Code: public class temp() extends java.lang.Object { public temp(){ } }
2nd case --- Java Code: public class temp() extends dummy{ }
javap Code:
public class temp() extends dummy{ public temp(){ } }
why for the above scenario it doesn't extends object class .. if it does implicitly then why it did not do in the first case instead why did the compiler extends Object class ?
how to 'implement' an interface and 'extend' a class. Now I want to try and recall the information by memory without using any reference material. Implementing an interface...
Java Code: //This interface will hold information for cell phones//Like saying... you can't BE a cell phone unless you have this information, at the very least
public interface CellInfo { public void model(); public void make(); public void androidVer();
}
//Now I implement the interface for a class called Galaxy, which is a class about a specific phone
public class Galaxy implements CellInfo public void model() { System.out.println("I'm a Galaxy S5."); }
public void make() { System.out.println("I'm made by Samsung.");
I have a GUI that I've been working on for a while now. What I am trying to figure out, is a way to have the user push a button, and when they do have the GUI extend out to the right with another table to use for Filter Data. Once They are done, I want them to push that button again, and the panel with the query data retracts and is hidden again, all without changing the size of the current GUI in question. I've tried a bunch of different things with setting preferred and Minimal values to my GUI, and I've played around with different Layouts (Border Layout.East, etc), but I can't seem to find a good working solution.
Ideally it would be slick if I could make my panel SLIDE out and SLIDE back in, which would look really cool, but I'd settle for something that just worked.
I want to extend hashCode method in my class. As we know that hashCode is generating with 32 bit. Now I wanna generate 64-bit hashCode for user given Input.. Input may be string or Integer.
Please let me know.. take me out from this problem..
MY code follows like this...
package hash_table; public class Hash_table { private int num; private String data; public boolean equals(Object obj) { if(this == obj)
I am working with a program where I am required to use a JFrame in a child class. The only way that I know how to access a JFrame is to do, example (public class Example extends JFrame), but since it is already extending the parent class, I am kind of stuck. I do not think that you can extend two separate classes, so..... I am stuck.
In the following program i have called the anonymous class of dev class.
interface emp { void desig(); } public class dev implements emp { dev e = new dev() //this line is throwing error ...works fine if i use emp instead of dev {
[Code] .....
i am getting stack over flow error as :
Exception in thread "main" java.lang.StackOverflowError at dev$1.<init>(dev.java:17) at dev.<init>(dev.java:16) at dev$1.<init>(dev.java:17)
[Code] .....
Is it because the jvm is not able to decide which of the 2 desigs() it has to load in the memory when its object is created in the main..??
Is there an advantage in using byte instead of int beyond the space savings? In my program, I'll never need close to the max value of a byte, let alone int, so it seems like a waste to make my primitives ints.
I need to send a byte array across a network. I know how to do this. (server->client)
byte[] myArray = new byte[]{0,1,2,3,4,5,6,7,8,9}; DataOutputStream.write(myArray);
... and I know how to receive it.
byte[] myArray = new byte[10]; DataInputStream.read(myArray);
When I send over one of these arrays, it ends up stopping storing values in the array when only about half the array is received, even though the array is sent from the server all at once. This results in the receiver's array, in this case, being something like {1,2,3,4,0,0,0,0,0,0}.
I can easily solve this - and already have - by simply adding a loop onto it and waiting for the bytes to all be received, as the method returns the amount of bytes actually read.
I am simply wondering if there is a better solution to this, as the current solution isn't that elegant. Did I do something wrong to cause only a part of the array to be sent first? Would it be better to use DataInputStream.readByte() to read off the bytes one by one rather than an array at once, and then store them in an array afterward? Would this cause a performance decrease as each byte is read individually? (I'm sending an array of several million bytes)
I am reading a book on Java and we are at a point where it is explaining type conversion in expressions. One of the examples shared has a byte being multiplied by itself and then assigned back to itself ...
byte b; b = 10; b = (byte) (b * b);
this is all good and dandy (that is, the code functions properly).
However, I am confused why I need to typecast here! Without the cast, the compiler screams, "Type mismatch: cannot convert from int to byte." Yet I haven't converted to an int?? It appears there was an implicit conversion.
The final value, 100, is clearly within byte's range of -127 to +127 isn't it? So I am lost as to what is the issue here.
