Similarities and differences between JAVA equals and "= ="

Recently encountered a problem in the project to add a weight, the sentence is invalid, has been unable to find the reason, so check the usage of equals, feel misty ~ ~

Add data to weigh, when sentenced to time time is "yyyy-mm-dd" such, but sentenced to fail, check a bit, the original equals before and after two

The object can be different when compared, but the data type must be the same, the date type of "2015-04-15" and the string type of "2015-04-15" is really different, think also ...

Here is the difference between equals and "= =":

Similarities and differences between JAVA equals and "= ="