java


String Constants Vs Resource Bundle in an Java web Application

牧云@^-^@ 提交于 2020-01-23 02:31:07
问题 From past Year are so, we have developed an application, in which we have used the static String Constants to store the Constants. Like public static final String PAYMENT_CHEQUE = "cheque"; Where Ever I Require i.e. in the jsp pages as well the Action class I will be refering to the Above String Constant I am thinking after reviewing the Resource Bundle, properties Files, My Question is Is there any performance hit if I use the properties file compared to Static String Constant? Which is

Exception in thread “main” java.lang.NumberFormatException: Not a version: 9

狂风中的少年 提交于 2020-01-23 02:28:05
问题 I am trying to run a Spark maven Scala Project in eclipse . when i run the scala class , i get this error : Exception in thread "main" java.lang.NumberFormatException: Not a version: 9 at scala.util.PropertiesTrait$class.parts$1(Properties.scala:184) at scala.util.PropertiesTrait$class.isJavaAtLeast(Properties.scala:187) at scala.util.Properties$.isJavaAtLeast(Properties.scala:17) .... what is wrong ? what is a version 9 ? 回答1: Scala does not work with Java 9 out of the box just yet - there

How do I check if a cell contains an image using Apache POI?

你。 提交于 2020-01-23 02:26:11
问题 I have the following block of code: File file = new File("myFile.xlsx"); // my file inputStream = new FileInputStream(file); System.out.println("reading"); XSSFWorkbook wb = new XSSFWorkbook(inputStream); XSSFSheet sh = wb.getSheetAt(0); // first sheet Iterator rowIter = sh.rowIterator(); while(rowIter.hasNext()){ // iterate over all rows System.out.println("New Row "); // notify of new row Row myRow = (Row) rowIter.next(); Iterator cellIter = myRow.cellIterator(); while(cellIter.hasNext()){

How to extract .class files from nested Jar?

大憨熊 提交于 2020-01-23 02:24:48
问题 I have a Jar file named " OuterJar.jar " that contains another jar named " InnerJar.jar " this InnerJar contains 2 files named " Test1.class " & " Test2.class ".Now i want to extract these two files. I have tried some piece of code but it doesn't work. class NestedJarExtractFactory{ public void nestedJarExtractor(String path){ JarFile jarFile = new JarFile(path); Enumeration entries = jarFile.entries(); while (entries.hasMoreElements()) { JarEntry _entryName = (JarEntry) entries.nextElement()

getSession() always creates a new session

我与影子孤独终老i 提交于 2020-01-23 02:17:12
问题 We have SecurityFilter class in our application by implementing Filter and our doFilter method looks like this. public void doFilter(ServletRequest sres, ServletResponse sreq, FilterChain chain) throws IOException, ServletException { LOGGER.debug(Logger.buildLogMessage("Starting SecurityFilter.doFilter")); HttpServletRequest request = (HttpServletRequest) sres; HttpServletResponse response = (HttpServletResponse) sreq; HttpSession session = request.getSession(); We have the following entry in

SpringBoot: Bypass OncePerRequestFilter filters

别等时光非礼了梦想. 提交于 2020-01-23 02:16:07
问题 I have a basic SpringBoot 2.0.5.RELEASE app. Using Spring Initializer, JPA, embedded Tomcat, Thymeleaf template engine, and package as an executable JAR file. I have created a Custom JWT based security filter JwtFilter : @Provider public class JwtAuthorizationTokenFilter extends OncePerRequestFilter { ... } But I want to Bypass this filter only for 1 specific request / method: "/api/v1/menus" , when is a POST But I don't know if it is possible in the WebSecurityConfigurerAdapter :

Dangling Threads in Java

穿精又带淫゛_ 提交于 2020-01-23 02:12:51
问题 What happens to dangling threads in Java? Like if I create an application and it spawns multiple threads. And one of the threads does not finish and the main program finishes before that. What will happen to this dangling thread? Will it stay in the thread pool infinitely or JVM will kill the thread after a threshold time period??? 回答1: It depends on if the thread has been marked as "daemon" or not. Daemon threads will be killed when the JVM exits. If there are any threads that are not daemon

Casting long to byte in Java

感情迁移 提交于 2020-01-23 02:06:32
问题 I am unable to understand the following: In java, long l = 130L; byte b = (byte)l; If I print the value of b, why do I get -126? What is the bit representation of long l? 回答1: Bytes are signed in Java - so the range of values is -128 to 127 inclusive. The bit pattern for 130 as a long, when simply truncated to 8 bits, is the bit pattern for -126 as a byte. As another example: int x = 255; byte b = (byte) x; // b is now -1 回答2: A byte is a sequence of 8 bits, which makes 2^8 cases = 256. Half

Print String with escape non printable characters

柔情痞子 提交于 2020-01-23 02:06:09
问题 I have this String String x="String containning special chars \u202C \n \u202C \u202C \u202C"; How can I print out this: String containning special chars \u202C \n \u202C \u202C \u202C ? Tried System.out.println(x.replace("\\","\\\\")); But that only prints String containning special chars ‬ \n ‬ ‬ ‬ Also tried String out = org.apache.commons.lang3.StringEscapeUtils.unescapeJava(x); System.out.println(out); But that also doesn't help. Any one with a suggestion or an API that I am not aware of

Casting long to byte in Java

守給你的承諾、 提交于 2020-01-23 02:06:06
问题 I am unable to understand the following: In java, long l = 130L; byte b = (byte)l; If I print the value of b, why do I get -126? What is the bit representation of long l? 回答1: Bytes are signed in Java - so the range of values is -128 to 127 inclusive. The bit pattern for 130 as a long, when simply truncated to 8 bits, is the bit pattern for -126 as a byte. As another example: int x = 255; byte b = (byte) x; // b is now -1 回答2: A byte is a sequence of 8 bits, which makes 2^8 cases = 256. Half

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