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What's the difference between Thread start() and Runnable run()
...thread and native thread. Thread.start() invocation make thread state move from new state to Runnable state. Runnable does not mean thread is running. Once the native thread has initialized, native thread invokes the run() method in the Java thread, which makes thread state change from Runnable to R...
What's the difference between getPath(), getAbsolutePath(), and getCanonicalPath() in Java?
... canonical path.
A canonical path is always an absolute path.
Converting from a path to a canonical path makes it absolute (usually tack on the current working directory so e.g. ./file.txt becomes c:/temp/file.txt). The canonical path of a file just "purifies" the path, removing and resolving stu...
What is the difference between up-casting and down-casting with respect to class variable
...ves a type check and can throw a ClassCastException.
In your case, a cast from a Dog to an Animal is an upcast, because a Dog is-a Animal. In general, you can upcast whenever there is an is-a relationship between two classes.
Downcasting would be something like this:
Animal animal = new Dog();
Do...
How to check if a file exists from inside a batch file [duplicate]
...
Try something like the following example, quoted from the output of IF /? on Windows XP:
IF EXIST filename. (
del filename.
) ELSE (
echo filename. missing.
)
You can also check for a missing file with IF NOT EXIST.
The IF command is quite powerful. The output ...
Lazy Method for Reading Big File in Python?
... noting that if he forgets the 'b' his data will very likely be corrupted. From the docs - Python on Windows makes a distinction between text and binary files; [...] it’ll corrupt binary data like that in JPEG or EXE files. Be very careful to use binary mode when reading and writing such files.
...
:: (double colon) operator in Java 8
...perator is used for method referencing. So, one can extract static methods from classes by using it or methods from objects. The same operator can be used even for constructors. All cases mentioned here are exemplified in the code sample below.
The official documentation from Oracle can be found he...
Cookies vs. sessions
...ide.
It is preferred to use sessions because the actual values are hidden from the client, and you control when the data expires and becomes invalid. If it was all based on cookies, a user (or hacker) could manipulate their cookie data and then play requests to your site.
Edit: I don't think the...
Java's final vs. C++'s const
... a new object, but it is not immutable - there is nothing stopping someone from calling any set methods.
final Person person = myself;
person = otherPerson; //Invalid
person.setAge(20); //Valid!
Java has no inherent way of declaring objects immutable; you need to design the class as immutable you...
How to create own dynamic type or dynamic object in C#?
... dynamic themselves, based on user defined entries. The examples here, and from Microsoft's ExpandoObject documentation, do not specifically address adding properties dynamically, but, can be surmised from how you enumerate and delete properties. Anyhow, I thought this might be helpful to someone. H...
How do I create a multiline Python string with inline variables?
...sked (in terms of syntax) are template strings. For example:
>>> from string import Template
>>> t = Template("This is an $example with $vars")
>>> t.substitute({ 'example': "example", 'vars': "variables"})
'This is an example with variables'
I should add though that th...