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  C vs Java Complete Comparison


Similarities: Java and C have same syntax operators. Difference—thinking Two paradigms: Java: Object oriented language C: Structured language Differences: --Syntax No preprocessor Java does not include a preprocessor and does not define any analogs of the #define, #include, and #ifdef directives. Constant definitions are replaced with static final fields in Java. (See the java.lang.Math.PI field for an example.) Macro definitions are not available in...

   C,Java,Comparison,Difference,Similaritie     2011-10-06 12:46:39


  Different types of keystore in Java -- Overview


Keystore is a storage facility to store cryptographic keys and certificates. They are most frequently used in SSL communications to prove the identity of servers and clients. A keystore can be a file or a hardware device. Three are three kinds of entries can be stored in a keystore depending on the types of keystores. The three types of entries are: PrivateKey : This is a type of keys which are used in asymmetric cryptography. It is usually protected with password because of its sensitivity. It ...

   JAVA,KEYSTORE,OVERVIEW,JKS,PKCS12,JCEKS,PKCS11,DKS,BKS     2014-08-18 02:09:54


  ByteBuffer in Java


ByteBuffer is introduced in java.nio since Java 1.4. It provides a way of representing raw structured data such as from a file or from network. It enables fast access of underlying data compared to traditional ways like byte[] Prior to Java 1.4, if you want to represent a structured raw data, you need to create a byte[] and then having a set of checks to delimit the byte array to get the expected tokens. There are three ways to create a ByteBuffer: Wrapping an exiting array by calling ByteBuffe...

   JAVA,BYTEBUFFER,ALLOCATION     2015-07-08 03:17:44


  Different types of keystore in Java -- PKCS11


PKCS11 keystore is designed for hardware storage modules(HSM). It's an interface to talk to the HSMs. It doesn't actually store any keys but provide a set of classes to communicate with the underlying HSM. The actual keys and certificates are stored on the HSMs. The reason for storing the keys and materials is to ensure security and efficiency. Since the keys are on the HSMs, they are safe to be stolen. All encryption/decryption operations are performed on the HSMs as well, this increase the...

   PKCS11,keystore,HSM,Java     2015-01-08 00:39:12


  A simple tutorial on writing Java native program


Java provides Java Native Interface(JNI) to enable developers to write programs which can utilize the underlying native libraries of the operating system. The benefits of writing native code are that they normally provide better performance compared to Java codes. Sometimes if you want to utilize some system specific functions you may also want to use JNI. One main drawback of writing native code is that your application may not be platform independent anymore. This is not what Java is desi...

   Java native interface, JNI, Native code, Sample     2015-08-15 08:28:15


  Different types of keystore in Java -- DKS


Domain KeyStore(DKS) is a keystore of keystore. It abstracts a collection of keystores that are presented as a single logical keystore. Itself is actually not a keystore. This new keystore type is introduced in Java 8. There is a new class DomainLoadStoreParameter which closely relates to DKS. To load different keystores into the single logical keystore, some configuration is needed. Here is the format of the configuration for grouping different keystores. domain [ ...] { keystore [ ....

   Java,keystore,DKS,tutorial     2015-01-20 02:27:27


  Using MemoryMappedBuffer to handle large file in Java


When handling large files, it will largely affect the process speed while using traditional FileInputStream, FileOutputStream or RandomAccessFile since they trigger lots of read and write operations. In Java NIO, a new way of handling large file is introduced which is to use MmeoryMappedBuffer to create memory mapped file. Memory-mapped I/O uses the filesystem to establish a virtual memory mapping from user space directly to the applicable filesystem pages. With a memory-mapped file, you can pre...

   JAVA,IO,NIO     2015-11-13 01:58:08


  Signature sign/verification demo in Java


Digital signature is commonly used in areas where data authentication and integrity are required. It is extremely important to have signature while transferring sensitive data from one peer to other peers through network since there might be malicious applications or man-in-the-middle attacks which may alter the data along the way. Java provides some APIs to generate and verify digital signature. One important class is Signature.  When generating the signature, a private key needs to be pa...

   SECURITY,JAVA,SIGNATURE     2015-11-21 09:48:12


  Comparable and comparator in Java


Comparable and comparator are two similar interfaces used to compare objects in Java. When we want to sort a list of objects such as Employee or User etc, we may need to implement these interfaces to make them comparable as we want. However, there are some differences between comparable and comparator interface.ComparableA comparable object is capable of comparing itself with another object. The class itself must implements the java.lang.Comparable interface in order to be able to compare its in...

   Java,Comparable,Comparator,Sort     2012-07-04 12:06:15


  Remote execute command in Java example


Frequently there is a need to logon to a remote system and run some commands or programs to get the output, many software can serve this purpose such as putty and gitshell.These software usually provide secure access to the remote system. But have you ever wondered what to do if you need to run commands on many different systems at the same time and get all these results back at a single place? Especially in big data era, many tasks may run on different distributed systems and you want o have a ...

   JSch, Example, Distributed system, SSH2     2014-12-12 03:20:19