According to the error message ("Could not find or load main class"), there are two categories of problems:

Main class could not be found
Main class could not be loaded (this case is not fully discussed in the accepted answer)
Main class could not be found when there is typo or wrong syntax in the fully qualified class name or it does not exist in the provided classpath.

Main class could not be loaded when the class cannot be initiated, typically the main class extends another class and that class does not exist in the provided classpath.

For example:

***public class YourMain extends org.apache.camel.spring.Main***
If camel-spring is not included, this error will be reported.

There is a recursive loop somewhere in your code (i.e. a function that eventually calls itself again and again until the stack is full).

Other browsers either have bigger stacks (so you get a timeout instead) or they swallow the error for some reason (maybe a badly placed try-catch).

Use the debugger to check the call stack when the error happens.

Currently Angular CLI doesn't support an option to remove the component, you need to do it manually.

Remove import references for every component from app.module
Delete component folders.
You also need to remove the component declaration from @NgModule declaration array in app.module.ts file

Here is a directive I wrote that expands on the use of the exportAs decorator parameter, and allows you to use a dictionary as a local variable.
***
import { Directive, Input } from "@angular/core";
@Directive({
selector:"[localVariables]",
exportAs:"localVariables"
})
export class LocalVariables {
@Input("localVariables") set localVariables( struct: any ) {
if ( typeof struct === "object" ) {
for( var variableName in struct ) {
this[variableName] = struct[variableName];
}
}
}
constructor( ) {
}
}
***
You can use it as follows in a template:
***

***
Of course #local can be any valid local variable name.

The origin of this error lies in the fact that each and every promise is expected to handle promise rejection i.e. have a .catch(...) . you can avoid the same by adding .catch(...) to a promise in the code as given below.

for example, the function PTest() will either resolve or reject a promise based on the value of a global variable somevar
***
var somevar = false;
var PTest = function () {
return new Promise(function (resolve, reject) {
if (somevar === true)
resolve();
else
reject();
});
}
var myfunc = PTest();
myfunc.then(function () {
console.log("Promise Resolved");
}).catch(function () {
console.log("Promise Rejected");
});
***
In some cases, the "unhandled promise rejection" message comes even if we have .catch(..) written for promises. It's all about how you write your code. The following code will generate "unhandled promise rejection" even though we are handling catch.
***
var somevar = false;
var PTest = function () {
return new Promise(function (resolve, reject) {
if (somevar === true)
resolve();
else
reject();
});
}
var myfunc = PTest();
myfunc.then(function () {
console.log("Promise Resolved");
});
// See the Difference here
myfunc.catch(function () {
console.log("Promise Rejected");
});
***
The difference is that you don't handle .catch(...) as chain but as separate. For some reason JavaScript engine treats it as promise without un-handled promise rejection.

First, the possible values for the hbm2ddl configuration property are the following ones:

none - No action is performed. The schema will not be generated.
create-only - The database schema will be generated.
drop - The database schema will be dropped.
create - The database schema will be dropped and created afterward.
create-drop - The database schema will be dropped and created afterward. Upon closing the SessionFactory, the database schema will be dropped.
validate - The database schema will be validated using the entity mappings.
update - The database schema will be updated by comparing the existing database schema with the entity mappings.
The **hibernate.hbm2ddl.auto="update"** is convenient but less flexible if you plan on adding functions or executing some custom scripts.

So, The most flexible approach is to use Flyway.

However, even if you use Flyway, you can still generate the initial migration script using hbm2ddl.

Let's say you want to print 11 as 011
You could use a formatter: "%03d".

You can use this formatter like this:
***
int a = 11;
String with3digits = String.format("%03d", a);
System.out.println(with3digits);
***
Alternatively, some java methods directly support these formatters:
***System.out.printf("%03d", a);***

You need to decode the byte string and turn it in to a character (Unicode) string.

On Python 2
***
encoding = 'utf-8'
'hello'.decode(encoding)
***
or
***
unicode('hello', encoding)
***
On Python 3
***
encoding = 'utf-8'
b'hello'.decode(encoding)
***
or
***
str(b'hello', encoding)
***

***
select
id,
case
when report_type = 'P'
then amount
when report_type = 'N'
then -amount
else null
end
from table
***

Most of the databases follow the basic syntax,
***
INSERT INTO TABLE_NAME
SELECT COL1, COL2 ...
FROM TABLE_YOU_NEED_TO_TAKE_FROM;
***

ive this CSS class to the targeted