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What is a JavaBean exactly?

...he serialization interface has no methods or fields and serves only to identify the semantics of being serializable. In other words, serializable objects can be written to streams, and hence files, object databases, anything really. Also, there is no syntactic difference between a JavaBean ...
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Why do I get a “Null value was assigned to a property of primitive type setter of” error message whe

...he primitive type from the getter. Ex: private Integer num; public void setNum(Integer i) { this.num = i; } public int getNum() { return this.num; } But in most cases you will want to return the wrapper class. So either set your DB column to not allow nulls, or use a wrapper ...
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How do I fetch a single model in Backbone?

...e; return base + (base.charAt(base.length - 1) == '/' ? '' : '/') + this.id; }, This approach assumes that you have implemented controllers with the hashbang in your URL like so, http://www.mydomain.com/#clocks/123 , but it should work even if you haven't yet. ...
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How to prevent custom views from losing state across screen orientation changes

...lass CustomView extends View { private int stateToSave; ... @Override public Parcelable onSaveInstanceState() { //begin boilerplate code that allows parent classes to save state Parcelable superState = super.onSaveInstanceState(); SavedState ss = new SavedState(superState); ...
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How to create standard Borderless buttons (like in the design guideline mentioned)?

I was just checking the design guidelines and wondering about the borderless buttons. I goggled and tried to find in the source but can't bring it together by myself. Is this the normal Button widget but you add a custom (Android default) style? How to make these borderless buttons (of course you ca...
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How do I handle too long index names in a Ruby on Rails ActiveRecord migration?

... Provide the :name option to add_index, e.g.: add_index :studies, ["user_id", "university_id", "subject_name_id", "subject_type_id"], :unique => true, :name => 'my_index' If using the :index option on references in...
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Cannot delete or update a parent row: a foreign key constraint fails

...dvertisers` ADD CONSTRAINT `advertisers_ibfk_1` FOREIGN KEY (`advertiser_id`) REFERENCES `jobs` (`advertiser_id`); ...is actually the opposite to what it should be. As it is, it means that you'd have to have a record in the jobs table before the advertisers. So you need to use: ALTER T...
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Pandas dataframe get first row of each group

... >>> df.groupby('id').first() value id 1 first 2 first 3 first 4 second 5 first 6 first 7 fourth If you need id as column: >>> df.groupby('id').first().reset_index() id value 0 1 first 1 ...
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Adding parameter to ng-click function inside ng-repeat doesn't seem to work

... Instead of <button ng-click="removeTask({{task.id}})">remove</button> do this: <button ng-click="removeTask(task.id)">remove</button> Please see this fiddle: http://jsfiddle.net/JSWorld/Hp4W7/34/ ...
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Cast Int to enum in Java

... Try MyEnum.values()[x] where x must be 0 or 1, i.e. a valid ordinal for that enum. Note that in Java enums actually are classes (and enum values thus are objects) and thus you can't cast an int or even Integer to an enum. ...