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How to get the first non-null value in Java?
Is there a Java equivalent of SQL's COALESCE function? That is, is there any way to return the first non-null value of several variables?
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Difference between Statement and PreparedStatement
... + "'");
preparedStatement.executeUpdate();
Eases setting of non-standard Java objects in a SQL string, e.g. Date, Time, Timestamp, BigDecimal, InputStream (Blob) and Reader (Clob). On most of those types you can't "just" do a toString() as you would do in a simple Statement. You could even refacto...
How to comment a block in Eclipse?
...le "//" comments and Ctrl-Shift-/ to toggle "/* */" comments. At least for Java, anyway - other tooling may have different shortcuts.
Ctrl-\ will remove a block of either comment, but won't add comments.
Note: As for Eclipse CDT 4.4.2, Ctrl-Shift-/ will not uncomment a "/* */" block comment. Use ...
Comparing Java enum members: == or equals()?
I know that Java enums are compiled to classes with private constructors and a bunch of public static members. When comparing two members of a given enum, I've always used .equals() , e.g.
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String.format() to format double in java
...alFormat.setRoundingMode(RoundingMode.UP);
Here are the imports:
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;
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What is the use of printStackTrace() method in Java?
... e) {
e.printStackTrace();
}
System.exit(0);
Calling println(e):
java.lang.NullPointerException
Calling e.printStackTrace():
java.io.IOException
at package.Test.main(Test.java:74)
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Is it possible to view bytecode of Class file? [duplicate]
Java source code is compiled into bytecode, which is actually in the class file. Is it possible to view bytecode of a compiled class?
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How do you import classes in JSP?
I am a complete JSP beginner. I am trying to use a java.util.List in a JSP page. What do I need to do to use classes other than ones in java.lang ?
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register int i;的含义 - C/C++ - 清泛网 - 专注C/C++及内核技术
register int i;的含义register声明的作用是为了提高效率。它明确要求CPU把变量始终保存在寄存器里面，直至它消亡。不过现代编译器都很厉害，根本不需要你多此一...register声明的作用是为了提高效率。
它明确要求CPU把变量始终...
朋友，这半年，你累吗? - 杂谈 - 清泛网 - 专注C/C++及内核技术
...这半年下来经历了多少艰难；这半年付出了多少不被人知的辛苦！
这半年真的很累，很累，但是所有的累只能一笑而过，这个累是自己经历的积累，这个累是自己身上应该有的责任。
除了坚强，别无选择。累了就抱抱自己...