My take to describe this in a more accessible way… In order to understand what Apache Camel is, you need to understand what are Enterprise Integration Patterns. Let’s start with what we presumably already know: The Singleton pattern, the Factory pattern, etc; They are merely ways of organizing your solution to the problem, but they … Read more
I figured out a method that works ~35% faster than your 6bits+Carmack+sqrt code, at least with my CPU (x86) and programming language (C/C++). Your results may vary, especially because I don’t know how the Java factor will play out. My approach is threefold: First, filter out obvious answers. This includes negative numbers and looking at … Read more
The transient keyword in Java is used to indicate that a field should not be part of the serialization (which means saved, like to a file) process. From the Java Language Specification, Java SE 7 Edition, Section 8.3.1.3. transient Fields: Variables may be marked transient to indicate that they are not part of the persistent … Read more
Use Throwable.printStackTrace(PrintWriter pw) to send the stack trace to an appropriate writer. import java.io.StringWriter; import java.io.PrintWriter; // … StringWriter sw = new StringWriter(); PrintWriter pw = new PrintWriter(sw); e.printStackTrace(pw); String sStackTrace = sw.toString(); // stack trace as a string System.out.println(sStackTrace);
for (Iterator<String> i = someIterable.iterator(); i.hasNext();) { String item = i.next(); System.out.println(item); } Note that if you need to use i.remove(); in your loop, or access the actual iterator in some way, you cannot use the for ( : ) idiom, since the actual iterator is merely inferred. As was noted by Denis Bueno, this … Read more
The version number shown describes the version of the JRE the class file is compatible with. The reported major numbers are: Java SE 18 = 62, Java SE 17 = 61, Java SE 16 = 60, Java SE 15 = 59, Java SE 14 = 58, Java SE 13 = 57, Java SE 12 = … Read more
StringBuffer is synchronized, StringBuilder is not.
Read all text from a file Java 11 added the readString() method to read small files as a String, preserving line terminators: String content = Files.readString(path, StandardCharsets.US_ASCII); For versions between Java 7 and 11, here’s a compact, robust idiom, wrapped up in a utility method: static String readFile(String path, Charset encoding) throws IOException { byte[] … Read more
The use of scriptlets (those <% %> things) in JSP is indeed highly discouraged since the birth of taglibs (like JSTL) and EL (Expression Language, those ${} things) way back in 2001. The major disadvantages of scriptlets are: Reusability: you can’t reuse scriptlets. Replaceability: you can’t make scriptlets abstract. OO-ability: you can’t make use of … Read more
The java <class-name> command syntax First of all, you need to understand the correct way to launch a program using the java (or javaw) command. The normal syntax1 is this: java [ <options> ] <class-name> [<arg> …] where <option> is a command line option (starting with a “-” character), <class-name> is a fully qualified Java … Read more