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Are there best practices for (Java) package organization? [closed]
... I saw a question answered here regarding the fine-grained organization of java packages. For example, my.project.util , my.project.factory , my.project.service , etc.
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Why does writeObject throw java.io.NotSerializableException and how do I fix it?
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java.io.NotSerializableException can occur when you serialize an inner class instance because:
serializing such an inner class instance will result in serialization
of its associated outer class instance as well
Serializatio...
Command line progress bar in Java
I have a Java program running in command line mode.
I would like to display a progress bar, showing the percentage of job done.
The same kind of progress bar you would see using wget under unix.
Is this possible?
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What is the “N+1 selects problem” in ORM (Object-Relational Mapping)?
...2.
Most ORM tools give you several ways to prevent N+1 selects.
Reference: Java Persistence with Hibernate, chapter 13.
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Jackson and generic type reference
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This is a well-known problem with Java type erasure: T is just a type variable, and you must indicate actual class, usually as Class argument. Without such information, best that can be done is to use bounds; and plain T is roughly same as 'T extends Object'....
When to use StringBuilder in Java [duplicate]
... generally preferable to use a StringBuilder for string concatenation in Java. Is this always the case?
9 Answers
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java : convert float to String and String to float
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Using Java’s Float class.
float f = Float.parseFloat("25");
String s = Float.toString(25.0f);
To compare it's always better to convert the string to float and compare as two floats. This is because for one float number there a...
Does Java have a HashMap with reverse lookup?
...ame for this type of data structure, and is anything like this included in Java's standard libraries? (or maybe Apache Commons?)
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How to convert a Map to List in Java?
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Using the Java 8 Streams API.
List<Value> values = map.values().stream().collect(Collectors.toList());
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Is null check needed before calling instanceof?
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The expression x instanceof SomeClass is false if x is null.
From the Java Language Specification, section 15.20.2, "Type comparison operator instanceof":
"At run time, the result of the
instanceof operator is true if the
value of the RelationalExpression is
not null and the referenc...