How to Check Null in Java
Use “=” to define a variable., Use “==” to check a variable’s value., Use an “if” statement to create a condition for the null., Use null as an unknown value., Use null as a condition for ending a process., Use null to indicate an uninitiated state.
Step-by-Step Guide
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Step 1: Use “=” to define a variable.
A single “=” is used to declare a variable and assign a value to it.
You can use this to set a variable to null.
A value of “0” and null are not the same and will behave differently. variableName = null; -
Step 2: Use “==” to check a variable’s value.
A “==” is used to check that the two values on either side are equal.
If you set a variable to null with “=” then checking that the variable is equal to null would return true. variableName == null; You can also use “!=” to check that a value is NOT equal. , The result of the expression will be a boolean (true or false) value.
You can use the boolean value as a condition for what the statement does next.
For example, if the value is null, then print text “object is null”.
If “==” does not find the variable to be null, then it will skip the condition or can take a different path. , It is common to use null as a default in lieu of any assigned value. string() means the value is null until it is actually used. , Returning a null value can be used to trigger the end of a loop or break a process.
This is more commonly used to throw an error or exception when something has gone wrong or an undesired condition has been hit. , Similarly, null can be used as flag to show that a process has not yet started or as a condition to mark to be beginning of a process.
For example: do something while object is null or do nothing until an object is NOT null. -
Step 3: Use an “if” statement to create a condition for the null.
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Step 4: Use null as an unknown value.
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Step 5: Use null as a condition for ending a process.
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Step 6: Use null to indicate an uninitiated state.
Detailed Guide
A single “=” is used to declare a variable and assign a value to it.
You can use this to set a variable to null.
A value of “0” and null are not the same and will behave differently. variableName = null;
A “==” is used to check that the two values on either side are equal.
If you set a variable to null with “=” then checking that the variable is equal to null would return true. variableName == null; You can also use “!=” to check that a value is NOT equal. , The result of the expression will be a boolean (true or false) value.
You can use the boolean value as a condition for what the statement does next.
For example, if the value is null, then print text “object is null”.
If “==” does not find the variable to be null, then it will skip the condition or can take a different path. , It is common to use null as a default in lieu of any assigned value. string() means the value is null until it is actually used. , Returning a null value can be used to trigger the end of a loop or break a process.
This is more commonly used to throw an error or exception when something has gone wrong or an undesired condition has been hit. , Similarly, null can be used as flag to show that a process has not yet started or as a condition to mark to be beginning of a process.
For example: do something while object is null or do nothing until an object is NOT null.
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